Ivan Gonzalez Alonso

About me

My basic training is in industrial design engineering, which covers technical aspects of engineering and applies them in product development, applying aesthetic and formal concepts. In this field, I have found a balance between my technical knowledge and my creative abilities.

Within the different areas of product design and development, my experience has allowed me to develop more in depth in the formal design of products and the realization of physical prototypes. With Fabacademy, I seek to expand my knowledge in the field of programming and electronics, as digital technologies are increasingly necessary.

I work based on the theory known as Design Thinking, because I think it provides the tools to innovate by focusing on people. It is an interdisciplinary methodology that iterates between the different design phases, allowing a product to be more competitive thanks to differentiation, adjusting to the user's real needs and speeding up the development in later stages of industrialization. Start by analyzing the problem to look for opportunities, followed by the phase of devising exploiting creativity and finding formal solutions that add value, continue with the development of the idea to make it viable and finally prototype to test ideas with users and improve them before of industrialization.

The innovation must be sustainable and the viability of the projects through must take into account the economic (Processes, costs, benefits ...), social (Trends, expectations, loyalty ...) and environmental aspects (Ecological footprint, models circular ...). I will keep those aspects in mind when carrying out the exercises and the project, seeking to reduce the environmental impact.

Exercises

Exercises

Here are the different exercises done during the Fab Adademy 2020 course. All of them has helped me to expand my knowledge of the world of digital manufacturing, either by acquiring new skills or strengthening those I already had.

The democratization of technology is encouraged from FabAcademy and aims to reach this knowledge to the greatest number of people.

If you want to know more about this world, you can enter in all the exercises and inform yourself.

Exercise 1 Principles and practice	Exercise 2 Project management	Exercise 3 Computer aided design
Exercise 4 Computer controlled cutting	Exercise 5 Electronics production	Exercise 6 3D scanning and printing
Exercise 7 Electronics design	Exercise 8 Computer controlled machining	Exercise 9 Embedded programming
Exercise 10 Input devices	Exercise 11 Applicationes and implications	Exercise 12 Output devices
Exercise 13 Interface programming	Exercise 14 Intellectual property	Exercise 15 Networking and communications
Exercise 16 Molding and casting	Exercise 17 Wildcard	Exercise 18 Machine design
Exercise 19 Project development

My project

Exercise 1: Principles and practice

Fab Academy 2020 has already started and therefore it is time to launch the final project, 100% DIY. The objective of the following exercise is to define the theme of the project and carry out a planning that helps to carry it out.

Problematic

Mobility in cities is changing, there are more and more personal electric vehicles. In the market you can find different alternatives such as scooters, segway and bicycles among many others.

On the other hand, the environmental problem due to our way of life of buying, using and disposing, is becoming increasingly evident. It is important to be aware and provide sustainable solutions based on the circular economy. The main objetive is to manufacture locally manufacturedare, reducing the necesary raw materials amd the waste; by reusing and recycling the largest number of components.

The change in mobility and in the enviromental problem, give rise to the need to recover obselot vehicles and make them a personal electrical transport.

Solution

In this case it has been decided to take a conventional scooter, since it can be found in most homes and most of the time it is thrown away when it falls into disuse. Having this idea as a starting point, now the design process begins to define all the specifications and start designing the solution in detail.

After completing this exercise, I was able to evaluate the scope of the project and carry out a planning that allows me to complete it satisfactorily. You will have more information in "My project" section.

Exercises

Exercise 2: Project management

The second exercise aims to design and program a web in HTML. This website should show all the exercises carried out during the FabAcademy 2020 course, in addition to a small personal presentation to make the rest of the members of the master known.

Mockup

Before starting the programming, some mockup were carried out to raise the design from the aesthetic and usability point of view. Here you can see the different ideas until you reach the final design, which is the same of this website.

Programming

In order not to complement the programming level and to be able to reach a web design with good usability, it has been decided to download a template and work on the content to be incorporated.

It has been programmed using Notepad ++ software, as it allows you to see the code and group it by type of element for easy reading. Although the template has several files that help create some effects and also make it responsive; only the INDEX.HTML files for the content and MAIN.CSS for the format have been worked on.

Obviously, it is not enough to write "only" text in the editor, you will also give instructions to the computer. In HTML, tags are used to create the algorithms. HTML pages are filled with what is called tags. These are invisible on the screen for visitors, but allow the team to understand what they want to show. Tags are easy to detect. They are surrounded by "gallons", that is, the symbols, like this:

< tag >

When the labels are 2 in 2, they allow what is between the two to obey a certain order and perform their corresponding operation. The following shows how a title would be clocaría:

< title > Text

When programming an HTML web, the code must start and end with the HTML tags and next to it is the information of the document, the .css files with which it has to be linked, the url of the web and other formatting options. Each part in turn is among the corresponding opening and closing tags, in this case head, body and footer:

< html >

< head >

< body >< /p>

< /p>

< footer >< /p>

< /p>

There is a large tag library for each case. If you want to enter an image, the first code is used and if you have to keep the format defined in the .css file the second:

< image nom="foto.jpg" />

< span class="image main">< img src="images/pic01.jpg" alt="" / >< / span >

There are different options for entering text (p, h1, h2…), but you have to take into account that each type of paragraph has some text properties that are defined in the .css file. Here are some examples:

< p > Text

< h1 > Title

< h2 > Title

Each page of the web has to be between the division tags (DIV) and each one of them has to be differentiated from the rest with the “article” tag. They must be previously defined on the main page so that you can navigate from one to the other:

< div id="main" >

< article id="intro" >

< h1> Title 1

< article id="intro" >

< h1> Title 2

To link one page to another through texts or images, the following code must be added to the desired element to make the reference:

< li class="image main">< a href="#exercise4">< img src="images/Photo.jpg" alt="" >

Using these concepts as a base and adding others (Tables, logos, social networks, links to other websites, alignment ...), you have reached the next website where you are browsing.

Upload

Once the design has been worked on locally, the GITLAB platform has been used to upload the web to the server and update it every time modifications are made. Thanks to this platform, the website will be public and linked to the FabAcademy website.

To be able to do this and control the versions, it is necessary to install the TortoiseGIT program and link it to the local folder where the web page is located. Thanks to this software, it is possible to make modifications and upload them to the server easily and quickly by right clicking on the folder and executing the "git commit" command. Once this is done, you just have to select the files to be updated and push.

Before uploading the first files, is necesary to create a SSH key in GitLab User Settings site. SSH key allows you to establish a secure connection between your computer and GitLab. To create this Key is need PuTTygen. PuTTY is an SSH and telnet client, developed originally for the Windows platform; is an open source software that is available with source code and is developed and supported by a group of volunteers.

When the folder is prepare to comunicate with Gitlab, is possible to start uploading files. This folder is going to be always the location of the web in local and is going to upload each of the files. After adding the key to GitLab site, is the time to upload the first web site version. Click with the right button on the mouse above repository folder to do it, and say to "Git commit -> "master"...".

After that, the TortoiseGit shows the files are going to Commit and upload (if it is the first time all files, but if it is after the first time it shows only the modified files). It is important to write a message in each uploading, it will helps us knowing why we have made this new upload.

The web is going to be updating until the FabAcademy 2020 course finish, so there will be changes during de developt.

Exercises

Exercise 3: Computer aided design

The work done in Commputer aided design exercise is shown below. This consists of modeling an object using design software. The object to be modeled is a scooter, specifically the one that will be used for the final project. The objective of this exercise is to model the product as it is today and make the necessary modifications.

The project consists of recovering a scooter for children that is in disuse, so that it adapts to an adult user and motorizes it. In order to model the product, each piece has to be disassembled and dimensioned.

Solid Works software has been chosen, since it is a very powerful and accessible software that I still do not control as I would like, since so far I have used to work mainly with NX. In addition, SW is a software that is used in FabLab and as I currently work in one, I have thought about specializing in this. Compared to NX, which is a very complex program that allows complex operations to be carried out, SW not only allows 3D modeling in a more simple and didactic way, but also allows rendering, simulations and preparing CAM files. For the edition of images Adobe Photoshop has been chosen to work with raster and Adobe Illustrator to work with vectors, since they are programs with great options to work on the images created in 3D. To create the rendered image, the Keyshoot software has been chosen, since it is very accessible and easy to use compared to V-ray, for example. Finally, 3Dmax software and Adobe Premiere stand out, which are the ones used to make the animation; the first one to generate movements and the second for postproduction.

SW modeling

The process to model the scooter in SW is explained below, highlighting the operations that have been used and showing the final result. The first thing we have to do is define what type of file we are going to work with; a piece, an assembly or a plan.

This exercise will begin with the modeling of each piece in 3D and at the end all will be assembled using the assembly option. Future 2D manufacturing drawings can be made with the drawing option. Once you have chosen the part option, the work window opens and you can see the different toolbars as shown in the image. At the top are the commands for drawing and modeling, in the central part is the workspace with the display options and on the left is the operation tree that will be completed when you start drawing.

Sketch

You start by making a 2D sketch and for this it is important to know all the concepts of relationship and dimensioning tools, to start you have to give the sketch icon of the toolbar. In the image you will see all the sketch tools; They are diverse and each one has its importance. Among these are the option of drawing lines, polylines, rectangles, circles, making symmetries or matrices, applying chamfers or rounding, making cuts and many other operations that allow drawing any type of sketches in detail.

Once drawn it is necessary to place the corresponding geometric relationships and narrow the drawing in its entirety, the objective is that it is fully defined and in SW be verified because the objects that are well defined are black, while the others are blue. Relationships between entities are those that appear in the property manager when we select the entity. If we select an entity, a different options box will appear than if we select more than one. The relationships of entities with a single entity selected are relationships in space, horizontal, vertical ... If we select two entities, the relationships will be between them, such as parallel, perpendicular, collinear ... The Smart Dimension tool is the standard way of giving distances or angles to two entities. It is essential that all the entities of the sketch appear related and do not have degrees of freedom. Once the sketch is defined, it is time to start modeling in 3D.

3D model

Starting from the sketches that have been drawn previously, we proceed to 3D modeling. The commands for models are in the features tab, where you can find the different operations that can be performed. It is important to note that the final form is created by extracting or subtracting material. Depending on the type of operation (Extrusion or revulucion) it is necessary to define some parameters or others, but in all cases a window will appear on the left with the parameters that we have to define. You can also do special operations such as rounding, chamfers, matrices, symmetries, sweeps ...

The first operation of any part is called the Base operation. In this exercise, the Base operation is created by extracting the drawn rectangle. From this operation you can start with the following, the objective is to start from a general geometry and gradually define the details. Care must be taken when modifying operations that are then used to parameterize subsequent ones, as errors may occur because the measurements or geometric relationships do not match.

Assembly

The following explaination is about how to join all the parts that have been modeled in 3D and thus achieve the final assembly of the product.

To be able to make assemblies, you have to control the position relationships, since these will help us to position one piece in relation to another; defining the type of relationship (Coincident, concentric, perpendicular ...). The first piece to be placed will be the one that cannot be moved and will define the origin of the assembly. It is important that the piece does not have degrees of freedom, unless you want it to have movement, otherwise it may move from its location. Once the assembly is finished, the software allows modifications and special operations such as creating an exploded view.

After introducing all the pieces and adding the relationships between them, it is possible to mount the skate completely. The image shows the final result of the current scooter with the most important measurements and an exploded view identifying each component.

Download old skate files

Those images have been extracted from SW and for the exploded one for example, there is a command within the program that allows moving the pieces without losing the assembly information. Then they have worked with Adobe Photoshop (for raster) and Illustrator (for vectors), since they are very versatile image editing programs and allow 2D illustrations to be made relatively quickly; specifically I have cleaned the image with photoshop and added the graphics with illustrator. The exlpanation of how is uso those programs is in the next exercise.

New design

After carrying out an analysis of the necessary components to motorize the skate and evaluate the modifications that must be done, some pieces have been modified and others have been added so that the scooter adapts to an adult user. The work process is the the same than how is made the old skateboard; defining sketches, modeling in 3D all the parts and assembling the pieces. The following image shows the final result with the dimensions.

The matinete is moved by a brushless AC motor powered by lithium batteries, which will transmit the rotation to the wheel using a toothed belt. All these competences are inside the scooter, between the upper board and the lower deck. The engine will be regulated by an electronic circuit connected to a display located on the handlebar to accelerate and see the desired information.

The redesign takes into account the different technologies and methods of digital manufacturing that must be worked during the Fabacademy course. To extend the wheelbase, it is proposed to cut the scooter in half and join it by means of two crossbars and a board at the top; These will be manufactured with the CNC milling machine. For the sandpaper of the skate and some separating pieces, it was thought to make them by laser cutting. The pieces of the display, the focus of the front light and the rest of the pieces that will be part of the box that will contain the electronics will be made with 3D printing. As the wheels are deteriorated, it has been thought to manufacture ones by the rubber molding technique, making molds with 3D printing. Finally, all the decoration of the skate will be done with the vinyl cutter, adding the graphics that make the product more attractive.

Download new skate files

Render

In order to illustrate better the idea, a rendering has been made with the Keyshoot software. Here you can see the materials and finishes that are being considered for the final project.

Exercises

Exercise 4: Computer controlled cutting

The following exercise consists in practicing and mastering some of the cutting technologies that are available in the FabLab, among which are vinyl cutting and laser cutting. For the design of 2D illustrations, use the programs that operate with Adobe Illustrator and Rhinoceros vectors; the first for the design because it allows more options to draw and the second to communicate with the machine more precisely. To continue deepen the possibilities of Solid Works, the prameterization is done using this software.

The different works carried out with these technologies are shown in next steps. For vinyl making stickers for the decoration of the FabLab and for the laser, a modular geometric created by repeating the same piece and joined by pressfit.

Vinyl cutting

The exercise with the vinyl machine has been oriented to create decoration for the FabLab, since there are currently many white walls that it is advisable to fill with images and information, such as the Fab Charter. In the face of the final project, it has been thought to make the decoration of the product and the iconography, but as the design is still preliminary, they will be designed and manufactured in later stages.

Design

The following explains how Illustrator was used to design the stickers. First, the software interface stands out. In the central part is the work table where the design will be carried out, in the upper part there are the parameters of the objects (Curves, texts, brushes ...) and in the right part are the quick access to the rest of the editing parameters.

It has been chosen to design the Fab Charter iconography to be placed on a wall of the FabLab, so this information will be visible and will help decorate the spaces. The Fab Charter will contain information on existing technologies, safety standards and other features of a FabLab.

The graphics were made using the text, pen and geometric figures command (circles, rectangles, triangles ...). The size and color have been modified to fit the final design.

Calibri typografy is chose becouse fits well with the FabLab logo has been chosen and which is easy to read from afar.

This is the final result of the Fab Charter after using the tools that have been explained. It has been designed in 3 languages; Spanish, Basque and English.

Download vinyl files

Fabrication

In the FabLab, the software that is configured and works to communicate with the machines is Rhinoceros. This is a 3D program that also allows you to work in 2D, as is the case. This works very similar to Solidworks, unlike the geometries do not have a tree that the history that can be modified. In the center of the interface is the workspace with the views that are configured, in the upper part are the properties of the file, on the left the different design tools and on the right the properties of the objects, in addition to the layers of work.

Next, the Illustrator design file is imported into rhinoceros. This way the design is achieved in vector format and it is only left to place each object in its layer. In this case there will only be two, one for the material and one for the figures to be cut. It is important that there are no double lines so that the vinyl is not cut too much and that you are closed, each being an independent object.

The wine cutting machine is a ROLAND, with a head that allows you to place a cutting blade or a drawing tool (pencil, marker ...). It works by rotating the material in and out, while the head that has a blade whitch moves from left to right. The material can be inserted from the front if it is a small piece and from the back if it is a roll. The computer is connected to the machine to make it work and on the right side is the interface of the machine to configure it.

Before starting to manufacture, you have to choose the colors to be used and organize the manufacturing.The material is vinyl on a base sheet that must then be removed, it is an elastic material and is easily cut with the blade.

As the dimensions of what you want to cut do not fit into small pieces, vinyl rolls have been used. To place them, you have to insert the folio from behind and lock it with the lever on the left, making sure that the material covers the sensor shown in the image and the clamping rollers are within the indicated white areas.

Once the material is placed, the machine must be configured so that it knows where the vinyl is and what size it is. For these it is necessary to alternate between the options of the machine and select roll, thus the machine will begin to measure. If you want to use a small piece, you must select the part option.

You have to draw a rectangle in Rhinoceros with the measures that appear on the screen after choosing the roll option. Then you have to put inside the designs that you want to cut. Now, is time to lounch the files to the machine, this is done by printing.

To let the computer know what the position of the vinyl is and its size, you have to enter the print settings and select the "get from machine" option.

To match the measures that the machine has read and those of the rectangle drawn in Rhinoceros, you must enter the "define" command and move the cutting window to fit one another.

Once all the steps have been done, click on print and the machine will start to work alone. You have to be close to make sure it cuts well and doesn't get stuck. When the head has stopped the machine, you just have to remove the locking lever and remove the material.

The work with the machine is already finished and now the manual work begins. First of all, the remaining material must be removed with a hook or punch, leaving only the desired graphics on the base.

Then the transfer is placed on the vinyl and then glued to the wall. This is an adhesive and disposable material, which serves as an intermediate support and flip the vinyl. To place it, it is necessary to put pressure on it with a rigid and flat material, but without any edge that could damage the material. Then you just have to remove the transfer from the support and the vinyl will remain attached to the transfer.

It only remains to place it on the wall. First it is put in position with the vinyl against the wall, then pressure is placed on the transfer and finally this material is removed, so the designs will stick to the wall.

After repeating this last step with each graphic and text, the entire Fab Charter panel has been assembled successfully.

Laser cutting

The main objective of the laser cutting exercise is to work pressfit between the different pieces, parametrically designing a geometry that is variable according to the thickness of the chosen material. In this case they will work on 3D puzzles that can work as a lamp or another product. In view of the final project, however, several pieces will be made that are necessary for the planned modifications.

For this exercise is propose a structure that forms a sphere. The face can be in the form of hexagons, triangles or any other polygon with different sizes. The pieces that form the dome are assembled and linked together until obtaining the dome, whose vertices must coincide with the surface of the sphere. Depending on the size, different results can be obtained.

The machine use during this exercise is one EPILOG, a medium size laser cutter with dimensions of 800x500mm. This machine is connected to an air extraction unit located on the right and compressed air directed at the head, it must be turned on for safety every time you go to work with the machine..

Cutting parameters

Before starting with the design of the geodesic sphere, it is necessary to test different cutting parameters to know how the machine works with the chosen material, which is double skin cardboard. For this, a template has been designed in Rhinoceros to test the different speed and power options of cutting and engraving operations.

Before manufacturing this board and deffining the cutting parameters, you have to place the material in the machine and calibrate the Z axis. This operation is called focus and is done by operating on the machine interface on the right side. To do this, go to the focus menu and use the joystick to raise and lower the table until the calibration piece shown in the image touches the cutting material.

Then you have to go back to the computer that communicates with the machine, open the file and organize the layers as done in the vinyl cutting exercise. Unlike this machine, the laser allows cutting, marking and engraving. In this case there is the layer of material, cutting, partial cutting and engraving. When the design is finished, you have to start printing it and just as with vinyl cutting, you have to match the cut window with the material drawn using the "Define" command.

Before launching the print, you have to choose the parameters of cutting speed and power. These vary if it is cut or engraved, so you have to specify it. In this case several combinations will be tested to have a wide range of options. Then you just have to click on print to launch the file to the machine.

Before the machine starts working, the air extraction and compressed air must be switched on. These help generate the appropriate cutting admosphere and prevent a flame from arising. The compressed air is turned on with the right wall switch and the extractor by turning on the one hand the left wall switch and on the other the ignition button of the extraction equipment that is next to the machine.

To start work you have to go back to the control panel of the laser cutter and enter the "Job" menu, here choose the job that has been sent from the computer and click on the "GO" button to start working.

You can launch several jobs at once and then manufacture them one by one from the control panel, the files are sorted chronologically. On the screen it indicates the time it takes to perform each operation, it is important not to move away since it is a machine that can be dangerous.

To manufacture this template, one operation had to be launched for each cutting and power variable. The result obtained is shown below, depending on this, the cutting parameters for the exercise will be selected. Cut (P40 / S40) and engraving (P10 / S60).

As the exercise consists in carrying out an assembly between pieces, it is important to know the material that evaporates the laser. This is called "kerf." In order to know what this value is, the rule seen in the image has been designed. This has several holes ranging from 2.5mm to 5mm, making 0.1mm jumps.

The ruler has been manufactured using the defined cutting parameters (P40 / S40), following the same steps as the previous template.

Once the rule is manufactured, you have to test the material, inserting it in the different holes and looking for which one fits best. After making several checks, it has been concluded that for the 3mm material, 3.6mm holes must be made.

Download cutting parameters files

Design

It has been chosen to make a geodesic dome composed of triangles and small connecting pieces. They have been sized so that they can form a sphere. Solid Works has been used as in the second exercise.

To parameterize in Solid Works, you have to enter the equations that are in the tree of operations of each piece. By right clicking on these and selecting the option to configure equations you can start to parameterize. The table that is opened contains all the dimensions and relationships used in the design and each one has a distinctive name to recognize it. To begin to parameterize, we must first add the variables we want to control, in this case thickness and kerf; These values ​​will be entered manually each time you want to modify the part. Then you have to go to each dimension and make it relate to the variables introduced, in this case putting the measure of 3mm of the material and adding 0.6mm to the holes by the kerf that has been calculated before. You just have to save the pieces and then repeat these operations with the following.

Once the triangle has been parameterized, the equations have been exported to a blog of notes that will serve to change it from now on.

Then the union piece has been created and to match it, the notes blog that is linked to the triangle has been imported; so the two pieces can be modified from this file.

Once the pieces have been modeled and the parametric work has been done, the values ​​of the defined variables (thickness and kerf) have been chosen and the plans have been prepared using Solid Works. Then it has been exported in .dxf so that you can have Rhinoceros and start manufacturing.

Download geodedesic sphere files

Fabrication

For manufacturing, the design has been imported into Rhinoceros, as in the previous occasions. The same steps have been carried out at the time of layering the layers and defining the cutting parameters in the printing.

Cutting machine files files

The different operations have been launched from the computer and manufactured using the machine's control panel. It is important to remember that you always have to turn on the extraction and compressed air before starting work. Manufacturing has taken 1h and 52min.

After cutting all the pieces, the excess material has been removed and the geodesic sphere has begun to be assembled, as seen in the image. It should be noted that the pieces are too small for the cardboard material, so they are fragile and assembling them with precision is complicated.

Exercises

Exercise 5: Electronics production

The next exercise is to manufacture and program a PCB board. This can analyze and control any previously scheduled task, in this case the board will be used to load programs from the PC to other devices. Before starting with the PCB board, a ruler is made to calibrate the milling cutter and see how it affects the design.xplication

Rule design

The following rule has been designed to calibrate the cutter size. Like the PCB, a FR1 (phenolic paper) plate with a copper surface will be used, which will be machined to leave only the circuit paths. In it you can see how much material the strawberry eats and what is the minimum width that it mechanizes.

To be able to machine the plate, you have to prepare the design in bmp format. and for this the photoshop program has been used. Just open the image and save it in grayscale, leaving a black margin at 0.1 mm to ensure that the mill does not mechanize the inside of the ruler.

Download rule design

Rule fabrication

In the image you can see the Roland CNC machine with which the machining will be carried out, this is contracted by means of 2 software that are explained later. More less, 0.1mm stepover have been used, a tapered to engrave the inside and a cylindrical for the outer cut.

To start manufacturing, the copper plate must be placed on the work table and to prevent it from moving, it is glued with double-sided tapes. Once the machine is switched on, press the "view" button so that the work table approaches, it is necessary that the door be closed.

Next, place the flat end mill for the engraving and calibrate the machine (x = 0, y = 0, z = 0). First, the strawberry is placed in the head and tied with the corresponding keys. The program used for calibration is the Roland V panel. First you have to configure the options in "user coordinate system" to work on the absolute coordinates defined by the user. Then the x and y axis are calibrated, for this the green and red crossheads are used, bringing the cutter closer to the bottom left of the plate. Once there, click on "apply" in the box where "xy origin" appears. To calibrate the Z axis, place the sensor in the center of the plate and bring the cutter closer to it, once there click on "detect" and the cutter will lower until it touches the sensor. Then just there to remove the sensor.

To launch the design to the machine, another DR Engrave program is used. You start by importing the design in bmp format.

The design is imported as a block and must be separated, for that right click on the object and select "drop polygons". This is done to have separately the inner part to be engraved and the outer part to be cut, so then you have to select all the curves inside and recreate the group of polygons. First, the engraving will be done and for this the option of creating a path is selected, giving a 0.15mm milling width (taking into account the width and angle of the flat end mill. Once done, select and select print to start machining.

In the print options there select the desired step and the depth of the pass. To make the engraving, a depth of 0.35mm has been selected and will be done in one pass. For depth cutting it is 1.6mm with 0.35mm passes.

Once finished, select "print" and the machine starts to machine itself, just wait until it finishes and clean the chips with a vacuum cleaner.

To end the rule just remove the plate and clean it. The image shows the final result and the precision that the machine reaches.

PCB Fabrication

The plate that has been chosen to manufacture is an ISP model and Brian's design has been taken. The PCB board to be manufactured serves to program other devices, being the one that will house the programs made on the PC to install them. Below is the scheme of the selected model, based on an ATtiny45 programmer.

To manufacture the PCB there you follow the same process followed in the calibration rule and use the same tools. As there to change tools again it is necessary to recalibrate the x, y and z axes. The result obtained before installing the components is shown below.

Download PCB design

Assembly

In the first place all the components that appear in the scheme of the plate have been compiled, identifying where each one is located. In the image you can see the components used.

Then all the components have been soldered using tin, checking the ammeter to see that the current passes and there is no short circuit. It is important that the welds have enough material to bond well, but be done very carefully so as not to damage components and cross connections. This has its difficulty since there is little space to work and the size is so small that it is necessary to use a magnifying glass to increase it.

Before starting the programming, you must connect the cable that will be used to connect it to other PCBs, this is done because the manufactured board has no program and the first time it is charged it is done through another board. para esto se utiliza unos conecteros de 3x2 y una herramienta con forma de tenaza para hacer la unidad.

Before connecting the boards to the PC, it is important that the 2 bridges are welded, without recognizing the manufactured board.

Programation

Before you can build and program the firmware onto your board, you need to set up your development environment. You'll use this setup for all of your AVR programming for the class. The setup differs a bit for each platform, but once the software is installed it should work more or less the same on each platform.

Add libraries

Atmel AVR Toolchain is a collection of tools/libraries used to create applications for AVR microcontrollers. This collection includes compiler, assembler, linker, etc. To expand the library and allow the programs to be recorded in the microprocessor, you must download "avrdude". Once both files have been downloaded, they must be extracted in the "program files" folder. Is very important to run these files as a administrator.

Download AVR Dude files

Compilation software

GNU Make is a tool which controls the generation of executables and other non-source files of a program from the program's source files. Make gets its knowledge of how to build your program from a file called the makefile, which lists each of the non-source files and how to compute it from other files. When you write a program, you should write a makefile for it, so that it is possible to use Make to build and install the program. So, the next step is to download and install in the directory “ program files (x86)” as a administrator.

Download GNU make software

Update path

To tell Windows where to locate all of the tools you've just installed when you type their names on the command line. Go to the Start menu and open the Control Panel, then go to System. From the left pane, choose "Advanced System Settings". Under the Advanced tab, click the "Environment Variables" button. Under User variables, select "Path" and click the Edit button. If you don't already have a variable called "Path", click the New button to create it, enter "Path" without the name, and fill out the value as described below. In this window, add the following three values in separate items (see screenshot below). Click OK on all of the windows you've opened.

Install driver

This tutorial assumes you are going to use a FabISP, FabTinyStarISP, or other USBtiny-based programmer. To connect the board to be used as a programmer and the one that has been manufactured, the 3x2 output cable that has been previously installed is used. Then connect the programer to the computer with USB to be able to load the program to the new PCB.

The USBtiny programmers use a generic libusb driver, but Windows 10's driver signing policy makes the installation more complicated. Fortunately, there's a tool that helps with this.

Download Zadig software

Before continuing with the programming, you have to do some checks to verify that the drivers have been installed correctly. Go to the start menu and search for "Git Bash" and start it. When you see instructions telling you to open your terminal in other tutorials, this is the terminal window you should use. These 3 steps must be done with the 2 connected boards.

make

Type make -v and press enter. You should see:

If you get a "command not found" error instead, re-check your installation of make and your path variable setting for typos.

avr-gcc

Type avr-gcc --version and press enter. You should see:

If you get a "command not found" error instead, re-check your installation of the Atmel toolchain and your path variable setting for typos.

avrdude

Type: avrdude -c usbtiny -p t45 and press enter. You should see:

This means that avrdude successfully found your programmer, but failed to talk to a target board (expected because we don't have anything conencted to the programmer right now.)

If you get a "command not found" error, check your installation of avrdude and your path variable or check your USB driver installation (the Zadig steps).

Build Firmware

Now connect the manufactured PCB directly to the programer given by Szilard made other years in the FabLAB, which is connectected to PC by USB. Then I connect my board to the programmer, if everything is well the two red led will be lighting (MAke sure the two bridge are solded).

Download the firmware source code and extract the zip file. Open your terminal program and cd into the source code directory, firstly define the local ubication of the folder (can not be Google drive folder) and run "make" to build the hex file that will get programmed onto the ATtiny45. When the command completes, you should now have a file called fts_firmware.hex. If the command doesn't complete successfully, something is wrong with your toolchain installation. Consult the error messages for information that will help you debug it.

Download firmware bdm files

Program the ATtiny45

First, update the Makefile for the type of programmer you're going to use to program your board. The Makefile, by default, assumes that you're going to use a programmer in another FabISP board. Edit the file called Makefile. In Windows is posible to use Notepad++, but in general whatever you use to edit your HTML code is probably an okay choice. In place os “?=usbtiny”, put the name of the programmer you are using. In this case usb tiny is ok, then save and close..

Run make flash. This will erase the target chip, and program its flash memory with the contents of the .hex file you built before. You should see several progress bars while avrdude erases, programs, and verifies the chip.I had trouble not recognizing my badge, since one of the badges didn't have the welded bridge. Once fixed it worked the first time.

If something went wrong, check:

• If the programmer is connected correctly and pin 1 on the connector matches up to pin 1 on the board.
• The board is well-seated in the USB port.
• ATtiny45 is installed in the correct orientation.
• Soldering looks okay on the ATtiny45 and ISP header.

Test USB

Now we'll check to make sure that the USB on your board works, before blowing the fuse that will enable it as a programmer. Unplug your board from the USB port and connecta without the programmer to the PC, check that the computer detects the USB. I have not had any problems, but if it doesn't work, you have to verify that the drivers for USBtiny are installed.

Once program is installed, connect your ISP programmer to your board one more time, and run make rstdisbl. This does the same thing as the make fuses command, but this time it's going to include that reset disable bit as well. You should see some progress bars, and with that, avrdude will never be able to talk to this chip again through the ISP header.

When the command ends, the USB port plate can be removed and to finish just remove the solder from the board jumper. The FabISP programmer with the usbtiny board is already manufactured, it can already be used to program other boards in future exercises.

Conclusion

The software has been installed correctly, but after talking with Nuria from FabLAB Leon, I realized that I shouldn't have welded the motherboard bridge. The problem was that you have to connect the manufactured board to an outlet (preferably to another PC so there are no problems) and mine only connected to the motherboard. I have tried to do this step to see if it is possible to program it and thus not remove the bridge from the motherboard, otherwise you run the risk of deleting your programming. I have reprogrammed the board and it has been programmed successfully, so for other programming exercises I will consider it.

Exercises

Exercise 6: 3D scanning and printing

In the following exercise you will work with different 3D manufacturing technologies, on the one hand the printing and on the other the scanning. It will begin by explaining each technology and how to calibrate it to start working with them, then different tasks will be performed with each one to meet the objectives.

3D Printing

A 3D printer is a machine capable of replicating 3D designs, creating parts or volumetric models from a computer-made design. This modeling is done by feeding the printer with a roll of this material, which when it passes through the extruder of the equipment is heated, melted and deposited layer by layer forming the object. After that, wait for the material to cool and can be handled.

These are the machines that will be used in this exercise, Ultimaker2 + and Sigma +, both of FDM technology (Deposition of molten material). The device is capable of generating three-dimensional solid physical bodies by adding layer by layer of a polymeric material, in this practice PLA will be used because it is the most economical.

Design rule

Before starting to print the piece chosen for the exercise, you have to make some checks with the printer to understand how it works. In order to know the different variables that can be manipulated when printing a piece in 3D, the following pieces will be printed. These can also help to know the different finishes and how the material behaves depending on the geometry, which can be helpful when designing a product for 3D printing. In the case of the octopus, the ".gcode" file has been modified so that it stops printing at mid-height and thus allows the interior to be discovered with its different fill patterns.

Download 3D printing design rule files

The Ultimaker and BCN3D printers have been used, in the images you can see the first one on the left and the second one on the right. The first step is to open the corresponding cure program for each machine and import the part. Once the piece is inserted, it is necessary to turn and move until the base of the piece is in the work plane in the correct position; This is done with the part editing commands that are on the right side of the interface.

In the following image you can see the variables used for printing. First of all you have to choose the material to be used, in this case PLA because it is the cheapest. It should be noted that a 0.4mm nozzle and a 0.1mm layer height have been used, so that the print quality is high and a satisfactory result is obtained. Regarding the infill, a 20% filling has been applied so that the pieces are printed as quickly as possible and spend less material. Most parts do not need support, so this option has not been selected except for the clearence and overhang rules that do. As there are several pieces separated from each other, retraction has been activated to ensure that there is no remaining material between the pieces. The other variables of speed, temperature or cooling, have been left by default as they come in the program.

Once finished, you have to click on the "prepare" button, to calculate the manufacturing time and prepare the .gcode file that we need to print. Once finished, this file must be saved on an SD card, as it is the memory unit recognized by the machines.

Before starting to print, you have to place the filament, in this case a blue PLA of 2.75mm thick. To install the material, the coil must be placed in its support (in the Ultimateker in the back and in the BCN3D on the sides). Then you have to act on the screen, in this you have to select the material option and within this the option of "material laod" (If there is a material beforehand it must be removed using the "unload material" command). Then you have to follow the steps indicated by each machine, although they are similar they have some differences. In general, the material must be inserted through the material inlet hole and wait for the rollers to grip it and move the row up to the print head. The material will be well loaded, when it begins to extrude material evenly through the extruder; When this happens, click on "OK" and this step will be completed.

Now you can start printing, for that you just have to insert the SD card in the corresponding machine and select on the screen the job you want to launch.

The printer will start to work alone and manufacture the part without having to interact with it. It is important to wait for the first layer to be manufactured to ensure that it adheres well and leaves nothing unprinted. If the printing is not homogeneous and there are areas that print poorly, you may have to calibrate the machine plate; while if the problem is that it does not adhere it can be solved with a little spray lacquer. Printing processes can take a long time (4 hours in this case), so it is important to check that you are printing well and not get stuck; If this happens, the machine must be stopped, the extruder cleaned and the parts re-launched. Fortunately it has printed me well at first.

When you have finished printing, you have to remove the piece with a spatula and remove the support material with a pliers. They can also be sanded if desired, although in this case it is not necessary because you want to see the actual result.

Below is the final result of the printed pieces. To facilitate its use in classes and workshops, some panels have been manufactured with laser cut and have been glued on them.

Object printing in FDM

Once the rules are finished, a piece must be manufactured and it has to be an object that cannot be manufactured by subtractive technology. In this case it has been chosen to make a hand tooll, which inside will have a screw that would be impossible to mount unless it is printed mounted. The tool must be able to move the head and for that the tolerance used is important, which can be chosen according to the result obtained in the corresponding rule. First of all you have to design the part and save it in ".stl" format, for this you have used the SolidWorks software.

Download 3D printing spanner design files

The BCN3D machine has been used, so that when loading the part the same process has been followed as for the design rules. The printing variables used are the same, since they have not given problems in the previous printing. The most important ALs are the PCB material, 0.4mm extruder, 0.1 layer height,% 20 infill, no support, no retraction and the rest of the default variables.

Download Spanner printing files

Once the variables are defined, you just have to prepare the file and save the "g.code" on the SD card that will be used to send the job to the machine. Then you have to enter the machine menu and launch the selected part. It is advisable to wait for the first layer to finish and watch it periodically to make sure it prints well and the extruder does not get stuck. In my case I had no problems and it ended well.

The final result is shown below and in principle it seems fine. But there has been a problem between the body part and the head, since there was a bridge that was too large and the material of the dune had adhered to the other, thus blocking the mechanism. The inner screw instead seems to have done well. To only use it, the wrench has been reprinted, but this time the head on one side and the body with the screw inside on the other. Once all the steps have been repeated, it has been possible to print that the screw rotates inside the body and the head can be inserted.

3D Scanning

The purpose of a 3D scanner is generally to create a cloud of points from geometric samples on the surface of the object. These points can then be used to extrapolate the shape of the object. If the color information is included in each of the points, then the colors on the surface of the object can also be determined. 3D scanners are different from cameras, it is a device that analyzes an object or a scene to gather data of its shape and occasionally its color. The model obtained by a 3D scanner describes the position in the three-dimensional space of each analyzed point. The information obtained can be used to build digital models that are used in a wide variety of applications. Among the different types of scanner that exist, you can use the 3D laser scanner with white light, which allows very good results and can also capture the color thanks to an additional camera.

The scanner used is the Einscan 2+, a professional high-resolution model that can capture the color. The scanner can be used with one hand or a fixed support can be used next to a rotating tray, in my case as I am going to scan myself, we will not use these accessories. This consists of several cameras and infrared sensors to capture the images.

To start, you must connect the scanner to the computer using the corresponding cables. The first one is connected directly to the PC via USB and the other to the electric current, the latter has a parallel cable that reconnects to the USB cable. To finish the assembly, the camera must be placed to capture the color at the top and connect the corresponding cable to the scanner.

Once the scanner is connected, the software must be started. First of all you have to define the type of file and the quality with which we are going to work, in this case medium-low quality so that it takes less time to load. In some low capacity computers it locks easily, this is because you need a powerful graphics card and a lot of RAM, in addition the scanner may stop working and you may have to restart the PC because it does not load.

Before you start scanning you have to calibrate the scanner. For this you must use the calibration panel that comes with the machine and follow the tutotial indicated by the software. There are several routines to zoom in and out of the scanner, with the panel in different positions. Once the scanner is finished it will detect it and finish the calibration.

To start scanning you have to press the "play" button that is both in the scanner and in the software. The machine will begin to emit light and capture the images, projecting the result in the software. The geometries you have recorded will appear in green and those not yet in purple; The objective is to make different passes until the object is turned completely and it is green. Once finished you just have to accept and save the final result.

Once you have finished scanning, you have to accept it and the software will start generating the files for the 3D model. This may take several minutes depending on the quality. It should be noted that the program repairs some errors and even fills gaps, this does it quite well and avoids having to retouch later. The following image shows the result in color, but you can also download the ".stl" file that you generated.

Download 3D scan files

Once the 3D model of my head is obtained, the result will be cleaned to improve it and make it more realistic. For this, Meshmixer software has been used.

To finish the exercise, the 3D model has been retouched with the Meshmixer software and printed on the BCN3D printer, following the same steps as in the previous parts. The following image shows the final result.

Exercises

Electronics design

The objective of the following task is to modify the design of a PCB to learn how to add components and learn to make the necessary checks to ensure that the board communicates with the computer properly. The PCB chosen for this exercise is the attiny44 model, for which we have all the components in the Lab.

PCB design

Eagle software has been used to start replicating the board before adding the new components (Led and button). This program has an extensive library of components and facilitates both the design and manufacturing of the board. It is necessary to load the library provided by the FabLAB to add the components we work with, which are not installed as standard.

Before starting to design the electronic scheme, the current board has been analyzed, looking for ways to add the button and the LED. The LED has to be connected to an analog leg of the processor and also to ground, it also needs a resistance before the 499Ω current arrives, otherwise the appropriate voltage will not arrive. The button, on the other hand, must be connected to the processor to a digital leg, to the power outlet and to the ground, in addition it is also necessary to add a 499Ω resistor so when the button is pressed avoid going along that path and change the state on / off of the button.

Once all components have been identified, a new scheme has been opened in the Eagle program, then all of them have been searched in the library and added to the worksheet to start making the scheme.

Once all the components have been placed, it is time to design the scheme so that the components are well interconnected to each of the branches of the scheme. For this, the design of the original plate has been followed and the LED and resistance on the free legs of the processor have been added.

Once finishing the scheme and verify that everything is fine. Then push the "SCH/BRD" button, Eagle will prepare the design of the board.

Once the board of your scheme shown, all the components and their connections will be shown randomly, so they must be ordered and all connections made so that there are no intersections and the space between them is not too small. This has been a complicated job since there are several interconnected components and she had to do several tests until I have successfully completed the scheme.

Now it only remains to export the file in .png format with high quality and in monochrome color, is necesary to hidde al the layers except the connections and contact pins for the components

Before starting manufacturing, the file has been opened in photoshop to make some tweaks. In my case the cable width seemed too small and just in case I have expanded it, I have also added the FabLAB logo and my name. Finally, it has been saved in .bmp format, to be recognizes by DR.Engrave manufacturing software.

Download electric scheme design files

PCB manufacturing

Before starting to manufacture, the machining tool must be selected and the machine calibrated (x-y-z). For this step, the steps explained in the electronic manufacturing exercise have been followed, using de V-Panel software. The milling cutters used are 0.1mm, the cylindrical for cutting and the conical for engraving.

Then you have to import the design into the DC Engrave program, put in the appropriate dimension and prepare the trajectories as in the previous exercise. I had to make the plate twice, because the first time I chose a step that was too small (0.1mm) and too deep (0.35mm); In the last test that went well, I used the values ​​of 0.15mm and 0.25mm. The other parameters of speed of rotation and displacement are the same as in the previous exercise.

Download board machining files

Once the engraving is launched, the outer cut must be launched and wait for it to finish.

The following image shows the final result of the plate before welding. It has been cleaned to remove copper debris that may interfere with the connections.

PCB assembly

Already with the manufactured plate, all the components have been searched and the material has begun to be welded. Below is the list of components.

The same welding process has been followed as in the previous exercise, using a soldering iron with a damp sponge to clean it, a 0.2mm tin wire and a sucker to remove unwanted material.

The result of the welded plate is shown here. Before proceeding to the programming part, it is necessary to make the necessary checks with the voltmeter to ensure that there are no short circuits the connections have been made correctly.

PCB programing

He thought of using arduino to program the board, since it is a widely used program and still did not work much with it. First, you have to load the libraries for the USBtiny board and the attiny44 processor drivers, which is what has been used. You can see in the next tutorial how to install the ATtiny microcontrollers in the Arduino libraries in Preferences.

Before writing the program, it is necessary to know how Arduino recognizes the different PINs of the attiny44 processor, for this it is necessary to see the designed scheme and see in the following image to which number each pin corresponds.

Now connect the motherboard to the computer via USB and with the 6 PIN cable to the new board, it also has to be connected via USB to the PC in order for the power to reach it. The LED of the mother board has to turn on.

Next, the program must be written so that the LED turns on when the button is pressed. First of all you have to define the variables with which you are going to work (LED and Button) and put the corresponding pin number in the previous image, in addition to defining whether they are output or input. Then you have to write in "void loop "the algorithm where it is defined that if current comes through the pin button the LED will turn on and if it does not arrive it will remain off. This happens because the resistance of the button causes that when pressed between the current and can only go to the processor because the resistance value is very high in comparison. It only remains to upload the code to plate and launch it, this is done by giving the Arduino arrow icon.

Download PCB arduino program files

The program has worked correctly and you can remove the programming board, connecting the new board to the computer so that the power arrives. In the image it looks like pressing the button turns on the LED.

PCB test

To end the exercise, different checks have been made using the multimeter. On the one hand, the value of each resistor (499Ω and 10kΩ) and that of the capacitor (1μF) have been measured. The voltage that passes through the LED has also been checked when the button is pressed, being around 5V in direct current. It has also been verified that the rest of the PIN through which it does not circulate is current. It is very important to learn how to use this tool, since it can help identify short circuits and errors in the values of the components, which may otherwise go unnoticed.

Exercises

Exercise 8: Computer controlled machining

The exercise involves manufacturing a large product using a CNC milling machine. We will start by carrying out the necessary tests to calibrate the machining variables (speed, displacement, gaps ...) and taking into account the results, the final product will be made. The image shows the machine to be used, which has a work table, a head that moves in 3 axes (xyz), a cabinet with the buttons necessary to start the machine and a remote control connected with a cable. the latter with which we control it.

Machine especifications

The milling machine we have is CNC TEC-CAM 1103 S-6.0, view image below. It is a subtractive process machine, process called too machining or metal removal. It consists of cutting the material with a rotary tool (milling cutter) of one or more lips. This cut is made by combining the rotation of the tool with displacement (of the tool, of the table or combined).

Different materials can be machined, cut both as milling or engraving of: methacrylate, PVC, DM, solid wood, brass, porexpan, foam and more. Important concepts to take in account for selection of end mills.

To start working with the machine, test designs have been prepared, with which you want to test the speeds of the machine to manufacture the product to be done in this exercise.

There are some important concepts to take in account in the Design Process. This process is not capable of making 90º internal pointed corners, due to the tool used. We have to prepare this corners first of machining if we want to assemble them with other parts. See examples below. mportant concepts to take in account in the Design Process. This process is not capable of making 90º internal pointed corners, due to the tool used. We have to prepare this corners first of machining if we want to assemble them with other parts. There are different assembly and structural types in which we can work, like CNC joinery, Digital joints, Living hinges and Flextures.

After seeing how the pieces have been, it can be concluded that the cutting speeds used are valid for manufacturing. It also shows how the pieces fit into each other without problems, so you do not have to modify the holes in the design, just sand a little each protrusion to remove the burr.

Product machining

The tests carried out will be used to design the following product, which is a large piece of furniture in which several pieces have to be mounted on top of each other. The following explains how the product has been designed, prepared, manufactured and assembled.

Design

The product chosen for this exercise is a hexagonal table at 2 heights. It is intended for one of the Deusto FabLAB workshops, where there is a free space that can be used to work at different heights.

The material chosen for the table is 18mm plywood, wide enough for the loads it will support.

Solid Works software has been used to design it, so you can check that the parts are well assembled and there are no collisions.

Download table 3D files

Once each part has been modeled in 3D and the assembly has been assembled, the plans for each part have been taken in .dxf format so that they can be entered later in the CNC machining program.

Before starting to prepare the files for machining, all planes have been joined into one with the Rhinoceros program. This has been done to order the parts within the table that we are going to machine and facilitate work in V-carve.

Define pads

Before starting work, you must choose the mill to be used. In this case, a cylindrical one for cutting and a conical one for engraving, both with a 6 mm diameter shank.

The V-Carve program will be used to prepare the manufacturing files. The first thing is to open a new file and put the measurements of the table to be machined, in this case 1220mm wide, 2440mm high and a thickness of 18mm.

Then you have to import the .dxf files that have been prepared in rhinoceros, in them you can see the 2D parts that you want to machine.

The next step in centering the design with the artboard, checking that all the paths are inside. Before starting the trajectories, a small modification must be made to the design. The milling cutter is cylindrical and is not capable of machining sharp edges, so it is necessary for the milling cutter to enter the edges until it is quite as shown in the image.

After placing the designs and making sure that all the vectors are closed, the different paths have been prepared. On the one hand the engraving with the conical tool and on the other the cut with the cylindrical one. The engraving will be done concentrically and with a depth of 1.5mm. For the cut 2 trajectories have been differentiated, the inner cut that will do it on the inside of the vectors and the outer cut that will do it on the outside. The two cuts will be 18.2mm deep and will do this in 3 passes, the extra 0.2mm depth is to make sure you machine all of the material.

In each case you have to choose the corresponding tool, in this case both are 6mm PERESCAMP, cylindrical or conical in each case.

Once each path has been configured, click on the "calculate" button to prepare the path. This must be repeated with each of the trajectories; engraving, inner cut and outer cut.

The program will show a simulation of the final result, drawing the different paths in the table. Errors can be identified here before they are released to the machine.

Now all the paths are saved in the USB to be connected to the machine. It is important that they are saved in .gcode archs (mm) format.

Download table fabricacion files

Machining

Now you can go to the machine, but safety is the first thing, so first we have to equip ourselves with gloves, glasses and helmets.

The following image shows the central panel of the machine. To turn it on you have to turn the red lever of the power and hit the ON button, then we will unlock the machine by inserting the security key and finally we insert the USB where we have saved the paths. In this panel there is also the button to turn on the suction of the machine so that it ties the board to the work surface, also on the rear side is the ignition of the air extraction to remove the chips; both will be used when machining.

Next, the different remote control commands with which you will interact during machining will be explained. Once the machine is turned on, the spindle must be sent to home, for that the SHIFT + 4 commands are used. Then there are the commands to calibrate the axes (x-y-z) and the commands to move the spindle on these axes manually. There is also the button to enter the path selection menu and the buttons to move in this menu. Then there is the OK button to select the file and within this menu, if 1 is given, it validates the selection. Now there is only the play button to start machining and stop to stop.

To start manufacturing, the first thing to do is place the material on the table and tie it. In this case, small jaws have been used at the ends and the air suction has been turned on to ensure that the board is flat. In order to fit the table comfortably, it is important to manually move the head all the way back.

Then the tool must be placed in the head, using the corresponding tool holder for the 6mm drills. The stone must be tied tightly using the fixed wrench and the one with the nail.

Before starting to manufacture, all axes must be calibrated. You start by manually moving the spindle to the bottom left of the table and once there, the origin of the x-y axes will be defined, giving the button XY = 0. To calibrate the Z axis, move the head inside the table and place the sensor, then press the SHIFT + 0 button so that the head goes down until the drill touches the previously placed sensor, this detects the height in Z of the material.

To finish you just have to enter the trajectories menu and select the desired file following the following button order (OK> 1 PLAY). It only remains to wait and be aware that nothing unexpected happens, for this reason we can not move away from the machine and we must have the remote control in case we have to stop machining. Once finished you have to remove the desired parts, clean the machining table and continue with the following table, repeating the same manufacturing steps.

Assembly

Once the machining is finished, all the parts must be removed and the corners sanded to remove the burr. The inserts have also been found to work properly and if they do not fit properly they have been sanded a little until the desired clearance is achieved. Then we have proceeded with the assembly, in the central image you can see all the ordered pieces. For the assembly, a rubber hammer has been used and it has been carefully beaten so that each piece fits well, it is a delicate process that must be done carefully and in order. Once assembled, it can be secured with white glue or small nails, although this can hinder if it is to be disassembled in the future.

Final result

Below is the final result after assembly. It has been proven to support the weight of several people and it is expected that the table will last over time, anyway if any part breaks we have already learned how to manufacture it.

Exercises

Exercise 9: Embedded programming

The next exercise is to program the board manufactured in exercise 7, so that when the button is pressed the light reacts by performing a programmed sequence. In addition, you want to know more about the operation of a micro controller, since it is the most important part of the board to learn how to program. The group assignament is at the end and it consist in comparing diferent controller families.

Data sheet

Before starting the exercise, the data sheet of a micro controller will be analyzed, the objective is to be able to know how to program and recognize the different legs both in the diagram and in the processor. In this case the model is an "attiny44", the same as in exercise 7. To learn more about this micro controller, the following manual has been used.

Download Attiny44 manual files

First of all, it should be noted that to program these boards you need an ISP programmer and in this case the FabISP used in exercise 5 will be used. On the other hand, it is necessary to differentiate the different PINs or pins of the processor, which in total There are 14. On the one hand there are those that power electrically next to the ground connection and on the other there are the communication channels for the different input / output that are programmed. These channels are differentiated in analog and digital, the first for components that have a range of action (Sensors, motors ...) and the second with the binary on / off states (Button, LED ...).

The following image shows the main sheet of the catalog with the data that must be taken into account to work with it, which in this case is the voltage and Hz at which it works. You can also download the data sheet to see more details of the controller

Download Attiny44 data sheet files

All this information will be taken into account from now on to program the board and execute the desired command.

PCB program

In this exercise, the board will be programmed so that the light blinks and communicates using morse code. In this case, when the button is pressed, the lights will say "hello". To program Arduino will be used, to implement the knowledge for the final project. This program uses a C + language and is compatible with the Attiny44 processor, just configure the software with the corresponding drivers, as explained in exercise 7.

To program the board, we have to do the same as in exercise 7, that is, write the algorithm with the IF, FOR and ELSE necessary for the LED to react in the desired way when pressing the button. For that, you first have to define the number of each PIN to name it in the program and for that you have to look on the one hand at the scheme presented next to the data sheer and compare it with the orientation in which the processor has been mounted on the board. Below is the program and it is possible to download it.

Download micro controller program files

When the programm is finish, lounch it using UPLOAD button. Here you can see how the button reacts when you press the button, as programmed.

To control the LED on and off times, the DELAY command has been used. Although the program works well, this command causes the board to be moments without reading anything and if you press the button in that time interval it does not work; having to press several times until it works. To solve this, the board has been reprogrammed, but using the MILLIS command, which controls the on and off time without blocking the micro controller, it continues to communicate.

the result is the same but without the problem that DELAY generates.

Test the board

To finish, I have Compare the performance and development workflows for different microcontroller families and see what is the difference between them using an oscilloscope. I have tried STM32 and ESP32.

The STM32 is a family of micro-controller of the ST Microelectronic company. This type of micro-controller is based on Cortex-M architecture. In particular we have probe the STM32F401RE. This micro-controller have a Cortex-M4 micro-controller. For the test we have used the Nucleo F401RE board. The program is very easy only configure and output pin and tongue it in a loop, so we can measure the change frequency with and oscilloscope. We have test a basic program in this micro-controllers using different methods: Register level configuration, Using manufacturer HAL library, Using a configuration wizard, STM32CubeMX, Using Mbed and Arduino in STM32.

Download different architectures program files

1_STM32: Register level configuration

Using register level configuration is the lower configuration method. It is the most complicated one but is in witch you have more control of the micro-controller.

As can be see, in the picture below, a frequency of 800kHz have been reached.

2_STM32: Using manufacturer HAL library

The manufacturer provide us a library called HAL (Hardware Abstraction Layer). This library simplify the configuration of the peripherals of the micro-controller.

The code using this library is more simple. You can use a data structure to define the configuration of the GPIO and then call a function to configure the GPIO.

As can be seen in the picture below a frequency of 616kHz have been reached, a bit lower than the previous test.

3_Using a configuration wizard, STM32CubeMX

The STM32CubeMX is a graphical tool that allows a very easy configuration of STM32 micro-controllers and the generation of the corresponding initialization C code through a step-by-step process. Using this tool is very easy to configure the correct clock rate.

The STM32CubeMX is a very good tool, it generate the initialization code and you have only to write the user code. In this case a speed of 3.5 MHz have been reached. This speed is higher than two previous examples, this increase of speed is cause because a correct configuration of the clock system.

4_STM32: Using mBed

Is a prototyping development platform that specially designed for ARM, it provides almost everything you need such as free SDK, HDK and web based IDE to develop IoT application. As can be seen in the picture below using mbed is very easy. Its a similar concept to Arduino. It is very easy to develop code using mbed but you loose some control of the micro-controller.

The speed reached using this method can be shown in the picture below. In this case the change frequency have been 1.37 MHz. It is more or less the half of the example developed using the configuration wizard but faster than the two first examples. This demonstrate that first examples have probably a bad configuration of the clock.

5_Arduino in STM32

It is not very common but Nucleo board can be programed also using Arduino. It can be done including Nucleo board to the Arduino IDE.

hen you have to go to the board manager menu and search the STM32 boards including them. Finally, you have to configure the correct board and the connection.

The result in the oscilloscope can be shown in the picture below.

Conclusion

After changing the clock configuration in the first two examples the results can be shown in the table below. he conclusion is that if you use low level register control you can get the faster results from the micro-controller, but it is is the hardest way to program the micro-controller. If you choose a high level abstraction library as mbed you can develop very quick but you lose performance.

Exercises

Exercise 10: Input devices

In this exercise you will learn how to insert input devices into a microcontroller. An ultrasonic sensor has been chosen to carry out the work, it is a device to measure distances. Its operation is based on sending a high frequency pulse, not audible by humans. This pulse bounces off nearby objects and is reflected back to the sensor, which has a suitable microphone for that frequency. Finally I am going to do some probes with this input device's reading analog and digital signals.

Working with arduino

Due to the confinement situation for Covid-19, the FabLAB is closed and I am unable to perform some of the FabAcademy tasks. For this reason I have acquired an Arduino ELEGOO startet kit will be used that contains everything necessary to start programming.

The software used is Arduino IDE, the same as in the previous exercises. To be able to work you first have to install the libraries that the Arduino MEGA2560 micro controller needs and for this you have to follow the same steps as in exercise 7. Then you just have to select the cards in the software tools, as shown in the image.

Below is the program used for the ultrasound sensor. Firstly, the PINs required by the sensor (chest11, ptrig12) are defined, in addition to exit PINs to be able to program an exit in the future. Then a working range between 0 and 500 has been defined, otherwise an alarm signal is output. The detected pulse is then transformed to centimeters (cm). You end up programming an alert when you approach the maximum and minimum measures previously established. In the image you can see different sections

To calculate the correct distance, it must be taken into account that the speed of sound in normal environmental conditions is 340 m / s. That is, it takes 58 microseconds for sound to travel one centimeter. Therefore, we can obtain the distance from the time between the emission and reception of the pulse by dividing the time it takes by the calculated time (This is multiplied by two since the wave comes and goes).

Before mounting the arduino board, you must carefully analyze the mounting scheme to lock each PIN in its place, you must also take into account the values used in the program.

Once the program has been launched, the plate begins to read it and the sensor begins to measure. To see the values, the graphic screen that shows the distance measured by the sensor in cm must be removed, and it also complies with the different established distance ranges.

Download arduino input program files

Programming my board

Now the same exercise will be repeated by manufacturing the plate and installing all the components.

Schematic design

Eagle software has been used to begin designing the exercise plate. The board will have an Attiny44 processor, a button, a sensor, an FTDI connector for the PC, another ISO connector to connect with other boards (This will be used in exercise 14 of networking) and other components such as resistors for it to work properly. This program has an extensive library of components and makes it easy to design and manufacture the board. It is necessary to load the library provided by FabLAB to add the components we work with, this can be seen in exercise 7 of electronic design.

Designing the board was kind of easy since the microcontroller and the ultrasonic sensor where using 5V, same Volts as from the USB. I have choose the Attiny44 microcontroller because of the extra communication connector pins and with this connector I would like to set up this board as a bridge for the networking week's assignment. After the schematics design I had to define the pathways for the board and I really wanned to make it without any bridges (0k resistors). The first 3 attempt where a failure and I ended up deleting everything (paths), but the fourth and last one was a success.

Once all components have been identified, a new scheme has been opened in the Eagle program, then all of them have been searched in the library and added to the worksheet to start making the scheme.

Once finishing the scheme and verify that everything is fine. Then push the "SCH/BRD" button, Eagle will prepare the design of the board. Once the board of your scheme shown, all the components and their connections will be shown randomly, so they must be ordered and all connections made so that there are no intersections and the space between them is not too small. This has been a complicated job since there are several interconnected components and she had to do several tests until I have successfully completed the scheme.

Now it only remains to export the file in .png format with high quality and in monochrome color, is necesary to hidde al the layers except the connections and contact pins for the components

Download Input device design files

Manufacturing board

Before starting to manufacture, the machining tool must be selected and the machine calibrated (x-y-z). For this step, the steps explained in the electronic manufacturing exercise have been followed, using de V-Panel software. The milling cutters used are 0.1mm, the cylindrical for cutting and the conical for engraving.

Then you have to import the design into the DR Engrave program, put in the appropriate dimension and prepare the trajectories as in the previous exercise. I had to make the plate twice, because the first time I chose a step that was too small (0.1mm) and too deep (0.35mm); In the last test that went well, I used the values ​​of 0.15mm and 0.25mm. The other parameters of speed of rotation and displacement are the same as in the previous exercise.

Once the engraving is launched, the outer cut must be launched and wait for it to finish.

The following image shows the final result of the plate before solding. It has been cleaned to remove copper debris that may interfere with the connections.

Download input fabrication files

Assembly

Already with the manufactured plate, all the components have been searched and the material has begun to be solded. Below is the list of components.

The same solding process has been followed as in the previous exercise, using a soldering iron with a damp sponge to clean it, a 0.2mm tin wire and a sucker to remove unwanted material.

The result of the solding is shown here. Before proceeding to the programming part, it is necessary to make the necessary checks with the voltmeter to ensure that there are no short circuits the connections have been made correctly.

Programming

I have to change same of the parameter of the arduino program to adapt to the ISP board and the ISP programmet, since it is a widely used program and still did not work much with it. First, you have to load the libraries for the USBtiny board and the attiny44 processor drivers, which is what has been used. You can see in the next tutorial how to install the ATtiny microcontrollers in the Arduino libraries in Preferences.

Before writing the program, it is necessary to know how Arduino recognizes the different PINs of the attiny44 processor, for this it is necessary to see the designed scheme and see in the following image to which number each pin corresponds.

Now connect the motherboard to the computer via USB and with the 6 PIN cable to the new board, it also has to be connected via USB to the PC in order for the power to reach it. The LED of the mother board has to turn on.

It is now possible to launch the program, although first make sure that the port selected in arduino is correct and that the libraries for ATtiny44 and FabISP are loaded, as explained in exercises 7 and 9. Once loaded, you can remove the programmer and the sensor board can work by itself. In the video you can see how it works.

Analog&Digital signal

One of the biggest pros of a oscilloscope is the possibility of the measurement of high frequency signals. To learn more about the speed of incoming signals we measured a arduino program.

Since we want to display the data of our board and the sensor on an oscilloscope, below are a few pictures showing the data of the HC-SR04. I recorded the sensor values at different distances. The following three images show different distances measured by the sensor.

Exercises

Applications and Implications

During this exercise, the final project will be advanced. First of all, a planning will be carried out to reach the end of the project on time, this was done from the first day, I did not expect so much and be better planned. Secondly, an exploded view of the product must be carried out, showing the different parts to be manufactured using the different FabLAB technologies, analyzing what is involved in terms of design, calculation, manufacture and assembly.

As I start an obsolete product and recover it thanks to the circular economy strategy, so some components will have to be remanufactured and other parts manufactured, looking for a low-impact product and recover the value of a product that could have ended up as waste. Since it is supposed to be part of an existing product and there are not many parts to manufacture, most of the cost will go to the battery (€ 80) and the motor (€ 50), while the printed parts and labor will be low (€ 70); adding a total € 200. The materials and components that are manufactured will be made in sustainable materials such as wood or PLA, avoiding polluting, high impact materials that are not recyclable. If possible, they must come from the local environment, so that the transport variable does not negatively affect the ecological footprint of the product.

Download new skate files

There have been different projects similar to these to be based on, all developed in other FAbAcdemy courses. In the following image you can see the outstanding projects, I will use them as a basis to see what complications they have had and to get ideas for my design; above all I will look at the electronic-programming since it is the part in which I have the least knowledge.

Project plan

As can be seen in the Gant diagram, the analysis phase has been carried out during the first month of the year and during the month of April it has been decided how the final design will be. During the research different products have been analyzed to see what types of engines and transmissions it uses, such as power, what materials are used and many more aspects. The objective is to evaluate and choose how the design of my scooter will be in all its aspects. Starting in April, you have to start designing all the pieces in their corresponding format (2D / 3D), order the components and start designing the plates that will be used to program the product. The objective is to start manufacturing in May and assemble everything during the month of June.

Scope of the project

Below is a general explanation of the product and highlights the different components that make it up. Each of them is shown in detail below.

After carrying out an analysis of the necessary components to motorize the skate and evaluate the modifications that must be done, some pieces have been modified and others have been added so that the scooter adapts to an adult user. The work process is the the same than how is made the old skateboard; defining sketches, modeling in 3D all the parts and assembling the pieces. The following image shows the final result with the dimensions.

The objective of the project is to achieve an attractive product that works according to market standards. After performing an analysis of the different aspects of the product, the following specifications have been defined. These are not data that must be strictly complied with, it is an approximation to choose the appropriate electrical components. Taking account all the parts, the cost is going to be near 350€.

Modified parts

Since the skate to be made is for children, the length of the base must be increased, for that it has been cut with rotaflex. The underside of the scooter has also been cut to make room for the battery, circuits, and motor. Then wooden slats have been manufactured that stiffen the base at its ends. Being manual work and only needing material for the slats, the cost will not exceed 10€.

CNC parts

As the base of the scooter has been cut to lengthen the base, a table is going to be made that serves for the user to climb on it and also stiffen the base. It is made of plywood, as methacrylate is not flexible enough and can be more easily cracked. As it is a vehicle and it is easy to get wet, this part will have to be varnished. It is the only part manufactured in CNC and is mounted with screws, so it is estimated that the cost does not exceed 30€.

3D printing parts

The parts to be 3D printed will first be the housings that cover the battery, circuit and motor. On the other hand, the accelerator and the screen casing will also be made with this technology. As the components arrive, these pieces will be designed in detail, for now there is only a preliminary 3D design. The price will be near 80€.

Electronic parts

The skate is moved by a brushless AC motor powered by lithium batteries, which will transmit the rotation to the wheel using a toothed belt. All these competences are inside the scooter, between the upper board and the lower deck. The engine will be regulated by an electronic circuit connected to a display located on the handlebar to accelerate and see the desired information. This circuit is also going to control of illumination, controlled by a sensor. Below is a list of the components, highlighting the material and the cost if known. The prices of all the components is going 170€ more or less.

Laser Cut

The only pieces that are designed in laser cutting will be the covers that will give access to the electronic components and some pieces that will serve as a base for the circuits or small plates to separate pieces. They are provided in methacrylate or plastic material, since it is a surface exposed to water and if it is wood it can deteriorate. The sandpaper will also be laser cut.This will be seen better in the final design, although it is expected that it will not exceed a cost of €20, since they are few pieces and very small.

Vynile cutting

All the decoration of the skate will be done with the vinyl cutter, adding the graphics that make the product more attractive. This can also be used for packging. It is not going to be a lot of material that is encesit and also being small details you can use scraps, so the price will not exceed 10 €.

Packaging

To finish, the product packaging will be designed, along with an instruction manual for manufacturing and assembly. This packaging must be quite rigid since the weight of the product is considerable and there are some delicate parts that need to be fixed; but it is very important that your impact is as small as possible. For this reason it has been decided to make cardboard that is a recycled and low impact material, on the other hand it must have several layers that provide it with rigidity. It will not be possible to design until all the components are available and their final dimensions are known, but the following image shows an example of what you want to achieve. An attractive aesthetic will be sought and in coherence with that of the product, using different formal codes to convey the image of a sustainable product that has been reused. The total price of the packaging must be less than 30€.

Exercises

Exercise 12: Output devices

The next exercise consists of testing with an output device, in this case we have chosen to use a motor since it is related to the final project. Now we are going to proceed with the design and manufacture of the plate that will be connected to the motor; at the end of the exercise different tests and measurements will be carried out to analyze the operation.

Working with arduino

Due to the confinement situation for Covid-19, the FabLAB is closed and I am unable to perform some of the FabAcademy tasks. For this reason I have acquired an Arduino ELEGOO startet kit will be used that contains everything necessary to start programming.

The software used is Arduino UNO, the same as in the previous exercises. To be able to work you first have to install the libraries that the Arduino MEGA2560 micro controller needs and for this you have to follow the same steps as in exercise 7. Then you just have to select the cards in the software tools, as shown in the image.

The small DC motor is likely to use more power than a MEGA2560 R3 digital output board can handle directly. If we try to connect the motor directly to a MEGA2560 R3 board pin, there is a good chance that it could be damaged by MEGA2560 R3 board. To do this use a power module provided by the arduino kit (Black board). The L293 is designed to provide bidirectional transmission currents of up to 1A with voltages from 4.5V to 36V.

The following code does not use a separate power supply, but instead uses the Arduino's 5v power. Note that this would be risky without the L293D controlling it. You should never connect a motor directly to the Arduino, because by disconnecting a motor you will get electrical feedback. With a small motor, this will damage your Arduino, and with a large motor, you can see an interesting effect of flame and sparks. After wiring, click UPLOAD to load the program and the motor will rotate clockwise and counterclockwise 5 times. Then it will continue to dramatically turn to the right. After a brief pause, it will dramatically rotate to the left. The controller board will then send the PWM signal to the motor, the motor slowly reducing its maximum RPM to a minimum and increasing to maximum again. Lastly, it is a stop for 10s until the next cycle begins.

Before mounting the arduino board, you must carefully analyze the mounting scheme to lock each PIN in its place, you must also take into account the values used in the program.

Once the program has been launched, the motor is moving. You can see the values in arduino pushing "monitor serie", the speed can be change otucjing the program.

Download arduino output program files

Programming my board

A board is to be programmed for an output device, in this case a DC motor. The objective is to measure and control the speed of the motor. For this, the electrical scheme will be designed, the board will be manufactured, the components will be assembled, the program will be installed and, finally, the necessary checks will be carried out.

Schematic design

Eagle software has been used to begin designing the exercise plate. The board will have an Attiny44 processor, a motor, several connectors (some will be used in exercise 14 of networking) and other components such as resistors to work properly. This program has an extensive library of components and makes it easy to design and manufacture the board. It is necessary to load the library provided by FabLAB to add the components we work with, this can be seen in exercise 7 of electronic design.

As a starting design I took Neil's bipolar stepper controller and I redesigned the board by adding a communication connector. I have used Eagle for the design since I'm starting to feel comfortable with the software. After the schematics design had to switch to board layout and define all the pathways.

Once all components have been identified, a new scheme has been opened in the Eagle program, then all of them have been searched in the library and added to the worksheet to start making the scheme.

Once finishing the scheme and verify that everything is fine. Then push the "SCH/BRD" button, Eagle will prepare the design of the board. Once the board of your scheme shown, all the components and their connections will be shown randomly, so they must be ordered and all connections made so that there are no intersections and the space between them is not too small. This has been a complicated job since there are several interconnected components and she had to do several tests until I have successfully completed the scheme.

Now it only remains to export the file in .png format with high quality and in monochrome color, is necesary to hidde al the layers except the connections and contact pins for the components

Download output device design files

Manufacturing board

Before starting to manufacture, the machining tool must be selected and the machine calibrated (x-y-z). For this step, the steps explained in the electronic manufacturing exercise have been followed, using de V-Panel software. The milling cutters used are 0.1mm, the cylindrical for cutting and the conical for engraving.

Then you have to import the design into the DC Engrave program, put in the appropriate dimension and prepare the trajectories as in the previous exercise. I had to make the plate twice, because the first time I chose a step that was too small (0.1mm) and too deep (0.35mm); In the last test that went well, I used the values ​​of 0.15mm and 0.25mm. The other parameters of speed of rotation and displacement are the same as in the previous exercise.

Once the engraving is launched, the outer cut must be launched and wait for it to finish.

The following image shows the final result of the plate before welding. It has been cleaned to remove copper debris that may interfere with the connections.

Download output fabrication files

Assembly

Already with the manufactured plate, all the components have been searched and the material has begun to be welded. Below is the list of components.

The same welding process has been followed as in the previous exercise, using a soldering iron with a damp sponge to clean it, a 0.2mm tin wire and a sucker to remove unwanted material.

The result of the welded plate is shown here. Before proceeding to the programming part, it is necessary to make the necessary checks with the voltmeter to ensure that there are no short circuits the connections have been made correctly.

Programming

He thought of using arduino to program the board, since it is a widely used program and still did not work much with it. First, you have to load the libraries for the USBtiny board and the attiny44 processor drivers, which is what has been used. You can see in the next tutorial how to install the ATtiny microcontrollers in the Arduino libraries in Preferences.

Before writing the program, it is necessary to know how Arduino recognizes the different PINs of the attiny44 processor, for this it is necessary to see the designed scheme and see in the following image to which number each pin corresponds.

Download arduino output motor program files

Now connect the motherboard to the computer via USB and with the 6 PIN cable to the new board, it also has to be connected via USB to the PC in order for the power to reach it. The LED of the mother board has to turn on.

Then you just have to load the program on the board through the ISP programmer (It is important to have the libraries installed as explained in exercise 7 and 9). In the following video you can see how the motor works once the program is loaded. I have had trouble with the arduino motor program to adapt it to the stepper motor I have used. So I have investigated what libraries are necessary and how you have to program them to work, that I have made a simpler program testing the movement step by step. After connecting everything, launching the program and turning on the board from a power supply, the step-by-step started to move once I have passed the 7.6V threshold.

Messure power

For measurement of the power consumption of an output device connection to a DC Motor. The motor is controlled by an A4950 driver. A PWM signal is applied to this driver and in function of Duty cycle more or less power is directed to the motor. I programmed it with sequence (2 seconds switched off, 2 seconds in 20% Duty cycle and 2 seconds in 40% Duty cycle). In this mode we can measure motor power consumption in each of this sequences.

First I connect 9V to the board using the Power supply, then connect the motor to the output of the driver (in PCB) and we can read the measurement of the current and power in the Power supply screen. This measurement is about all in the PCB, not only motor’s consumption. With the Oscilloscope we have measured resistor signal. A voltage signal proportional to the current of the motor. The SHUNT resistor is 0’25 Ohm, so we have to divide the voltage with this number (V=R·I).

The consumption of the PCB with motor switched off is about 0,144W, and when motor is running its consumption is added to it. In the first sequence; Motor is consuming (1,605-0,144)=1,461 Watts, and in the second sequence (3,216-0,144)=3,072 Watts.

Exercises

Interface programming

In this exercise, the data collected by the plate designed in the exercise of the device will be displayed on an interface, where a distance sensor shows the measurement at all times. For this, the software Processing will be used, which is compatible with the Arduino UNO program and the components that have been used.

Download arduino input program files

Processing is a Java-based open source integrated development environment and programming language. Once Processing is installed on the PC, you will see that it is very similar to the Arduino IDE, since it is based on Processing. Just change the PLAY button that is used to start the environment created with the program, and the STOP button that is used to stop it.The libraries for the ATtiny44 processor must first be installed and loaded.

First of all you have to know how it is programmed in Processing. You will see that the structure of the program is very similar to an Arduino program. Since Processing is a Java based development environment, there are many functions to create visual shapes and figures. First of all, we must know that the display screen we created with Processing is a pixel graphic, each one registered with a coordinate (X, Y). The origin of the graph is located in the upper left corner with the coordinates (0, 0). If we add to X, we move to the right. If we add to Y, we scroll down.

This is the program used to display the sensor reading. The program has a header where the port of entry is defined. Since it is displayed in pixel, it is necessary to take them into account to size the graph that we want to plot. We connect Sensor 136B5B to Arduino, arduino recognizes it and sends a value to Processing, with which we can modify values within processing. In this case, the example is a circle that changes size according to the distance the subject is from the sensor. It is important in Processing to have the Arduino AP-Sync library installed. The code also includes the flashing of a led light connected to the Arduino as I get closer or closer. The value named "distance" is what we will send to Processing.

Download processing interface files

Here you can see the final result, where the arduino board is connected and the program is launched. On the screen you can see the graph that shows how the measurement captured by the sensor changes depending on how close or far the object is from the sensor.

Once I was able to go back to the LAB, I used the analog input board from exercise 10 and used it to visualize the interface by adapting the arduino program to the ATiny44 board to communicate with Processing software. I only had to assign PIN 10 to Trigger and 9 to Echo.

Then I have loaded the program on my board and you can see the interface where a sphere moves as a function of the distance that the ultrasonic sensor reads.

Exercises

Exercise 14_ Intellectual property

The final project consists of in an open source electric scooter, starting from an obsolete scooter and doing a circular economy exercise to be able to recover it. The project is called "Scooter RIO" (Recover, Upgrade and Open). The necessary searches have been made to ensure that there are no matches with any other similar invention. The final project is shown in the image.

For this reason it is very important that all files are free to use but do not allow others to generate income, for this reason the following guidelines on intellectual property will be followed. In this case, nothing will be patented either, so the design is completely free. None of the processes or knowledge involved in this project can be considered my invention, it is the result of an upward trend and I have relied on existing projects, wanting to improve them applying the vision of a user. I relied on existing knowledge and information, therefore I do not claim to have any exclusive rights to do so. If the fact that this object exists has had an effect on someone's life or experience, all I want to do is mention, attribute, and cite it as its author

Creative Commons

Creative Commons (CC) is an American nonprofit organization dedicated to expanding the range of creative work available for others to legally build and share. These licenses allow creators to communicate which rights are reserved and which rights are waived for the benefit of recipients or other creators. In summary, they are associated visual symbols, explains the details of each Creative Commons license.

Creative Commons licenses do not replace copyright, but are based on it. They replace individual negotiations of specific rights between the copyright owner (licensor) and the licensee, which are required under "all rights reserved" copyright management, with "some rights reserved" management. "which employs standardized licenses for reuse cases where there is no commercial compensation sought by the copyright owner. The result is an agile, low-cost, low-cost copyright management regime that benefits both copyright owners and licensees.

I have used the following page (https://creativecommons.org/choose/#metadata) to get the license icons and the code to upload to the web. You just have to follow the steps shown in the image and defining how you want to protect your idea. I have created my own CC license for my work on the Creative Commons website, it allows me to obtain a license by following some simple steps.

Copyright

Copyright is a form of intellectual property, applicable to certain forms of creative work, and is the most widely used license. The Copyright symbol is represented by a "C" inside a circle. Normally, no one except the author can use or modify the product, that is, the work has an owner and must be paid in addition to asking permission to use it. But let's give the case that you get the work of this author or company, because you CANNOT legally redistribute it, because the only one qualified for it is the author of the work, that is, this license only allows you to have the work for personal use. If these rules are violated, they may be committing a crime, although it should be noted that this type of regulation makes it difficult for the open sourse culture to expand.

I would like to provoke people to make the economy circular with an attractive and highly useful product. I do not intend to generate any direct income from the artifact created as a final project, but I do want it to expand and in passing, to recognize the author. Thus, if someone wants to take my project and improve it, adapt it, transform it and share it, they are free to do so, they will not be protected under a Copyright license.

Dissemination

My objective for this project is to go ahead with it and prepare some workshops so that other people who do not have the knowledge or the sufficient means can get FabLAB to manufacture their own electric scooter from a normal scooter that is obsolote. This project is not thinking to copy and paste, that is, it is necessary to adapt certain components to each scooter and also sometimes others may have to be repaired. For this reason, it has also been thought that a service is needed that allows inexperienced users to carry out the project, the aforementioned workshops being the best way. In this way, it is also possible to value FabLAB and its workers, facilitating the process and in turn educating in the maker culture. For this it will be necessary to prepare the material in a didactic way and by steps so that the students / users understand better each step of the manufacturing.

As a secondary objective, I would like to present the project to a fair or circular economy contest so that the idea expands and other people can manufacture their scooter or even replicate the workshops. For example, it can be presented at the different stands that the FabLAB in Deusto puts up, although they could look for others. Finally, it will be uploaded to the different forums and platforms of the FabLAB and the different Maker communities that are on the web.

Exercises

Exercise 15: Networking

The next exercise is to make two plates communicate with each other. The boards in Exercise 10 (Input device) based on an ultrasonic sensor and Exercise 12 (Output device) with a motor will be used. To start, each board must be programmed separately, although this has been done in the previous exercises. The objective is to control the speed and the motor with the sensor, that is to say, depending on whether the motor is made or moved away, it will respond accordingly. For this I am going to connect the sensor board through the FTDI connector, using the TX and RX pins and the Servo through the pins that I connected to the Serial Bus.

A program similar than used in exercises 10 (input) and 12 (Output) has been used and it has been adapted to work with the ISP programmer and the board that it manufactured. It is important that the connections coincide the same as in the previous exercises. Below you can see the program used. To get started, I had programmed each board separately and configured it to send information over the serial to the computer. From the serial monitor window I was seeing the correct measurements from the sensor board and the correct steps from the board step by step. The communication protocol is a simple serial communication protocol (serial.write), the same communication is used to read the sensor values on the Serial Monitor and the jumper board uses it to define the steps and speed step by step. The node board is a kind of emitter, and both the PC and the bridge board use this emitted information to show or move the step by step.

Download networking files

When the program has been carried out, you only have to connect the boards to each other and each one to the computer via USB. Then you just have to launch the program in Arduino to load it inside the board.

Once the boards are programmed, they connect to each other and the codes are launched to start working. It is important to have configured arduino with the necessary libraries (Explained in exercises 5 and 7). Below you can see how the motor reacts according to the data collected by the ultrasonic sensor.

The motor has started to move as it made an object to the sensor and move it away, but before being able to record, some component has burned because the voltage has increased too much (more than 10v). Taking into account the situation of the Covid for which I have limited access to the FabLAB and that very short of time, it cannot replicate the board. For again I have to be more careful when raising the voltage or the voltage that reaches the plate, from the regular I have already seen that they can burn.

I redo the assignment adapting to I2C communications (Serial bus), being possible to connect to varius board and recognized then. I2C is a synchronous, multi-master, multi-slave, packet switched, single-ended, serial computer bus invented in 1982 by Philips Semiconductor. The first board is the I2C master which is also input device slave and the second a I2C output device slave. The master board check if the input device is switched on and if it is sends to the output device a message to be activated.

Therefore you have to create 2 programs, one for the master board with the input slave and an other one for the output slave. Also this program can works wich more than one board. You have to assign them a numbering so that they recognize each other and this is done with the wire library as shown below.

Now it would only be necessary to connect the plates and check that they recognize each other, which has not been possible due to the fact that the plates were burned in the tests. Although it has been analyzed with experts and it seems that everything is correct.

Download networking I2C files

Exercises

Exercise 16_ Molding&Casting

The next exercise involves making a product using molding techniques. For this task it is necessary to use the milling machine and the objective is to make a 3D design to test this type of operations that I had not done before. First of all, an analysis will be made of the different materials that can be used to cast in the mold, which are found in the FabLAB.

Test card comparation

The material which we are going to use to mill molds will be a machineable wax, in this case a blue Ferris File-A-Wax you can see below. Machineable wax is an extremely hard wax with a high melt point that has been formulated to deliver exceptional machining properties with high resolution detail.

There are small but important differences in machining waxes for certain applications. In our case, we are going to use blue one, which has 52D Shore hardness, the softest one in those Petroleum hydrocarbon wax blends in block Ferris has. It is a 454 g wax block, and it will be enough to learn how to work with this kind of materials and get our molds to cast.

Download material datasheet files

SMOOTH-SIL 940r

Also known as addition-cure silicone, platinums exhibit the lowest long-term shrinkage and have the longest library life of all mold rubbers. While good for making molds for casting a variety of materials, platinums also have application and physical properties that other rubbers do not. As a result, they are used for other applications. For example, some are certified “skin safe” and can be applied directly to human skin. They are also used for making prosthetic and orthotic devices, skin safe appliances and effects, etc. Some are certified “food safe” for culinary applications.

These silicones exhibit good chemical, abrasion and heat resistance. Materials such as plasters, concrete, wax, low-melt metal alloys or resins (urethane, epoxy or polyester) can then be cast into these silicone rubbers without a release agent. Smooth-Sil Platinum Silicones are used for rapid prototyping, wax casting (foundries and candle makers), architectural restoration and for casting concrete. Smooth-Sil Platinum Silicones cure at room temperature with negligible shrinkage. With 40A Shore hardness in our case, as you can see below.

It is important to understand safety considerations too: It is necessary to use in a properly ventilated area, wear safety glasses, long sleeves and vinyl gloves to minimize contamination risk. The mixture that should be done is: 100 silicone (part A) + 10 catalyst (part B), and be careful with its pot life: this mixture working time is 30 minutes only. Although not usually necessary, a release agent will make demolding easier when pouring into or over most surfaces. The only inconvenient would be that we have not degassing systems and vacuum degassing is recommended to eliminate any entrapped air. We will see.

FORM-SIL 25

It is a flexible silicone for pouring molds. If it is needed can be thickened with THi-Vex thickening agent. Its hardness is Shore A25 and its color is white. FormSil 25 has a low viscosity and pours easily without degassing. The mixture that should be done is: 100 silicone (A component) + 5 catalyst (B component).

FORM-CAST RHINO

FormCast Rhino is an easily pourable, thin-flow polyurethane cast resin that is suitable for many applications such as: decorative objects, prototypes, vacuum drawers, support caps, etc. Can be obtained a pasteous resin by adding fillers. For this material, the working method is: Stir the individual components well before use. Weigh or measure both parts accurately and assemble in a clean and dry container and mix for 30 to 60 seconds (for the mixing cup, best use PP or PE plastic cup). Avoid contact with moisture as this will cause foam formation of the resin. It is important to understand safety considerations too: Avoid contact with skin and eyes. It is recommended to wear protective clothing such as: a long sleeve shirt, laboratory gloves, safety goggles and carbon foot mask.

COGELSA ULTRAGREASE TF SPRAYr

Teflon and non-toxic spray grease. Great resistance to water, steam and high temperatures (tips up to 200ºC). NSF H1 certification for accidental contact with food. We have used it as release agent when we casted Smooth-sil into Wax machined mold.

My design

Before explaining what the exercise will consist of, it is worth summarizing how it will proceed. First the product to be manufactured will be designed, secondly the parts of the mold will be 3D modeled, then the mixed material will be seen and finally the excess material will be removed when it is already dried.

Design molds

For the exercise it has been decided to make a set ofsurf quilha, so you have to start modeling one by one the three parts (Central, left and right).

SW is then used to prepare the mold cavity. This is done by assembling and placing the parts to be molded. Then you just have to remove the intersecting geometries and remove the 2 pieces of the mold. Finally the channels for casting will be made at the bottom.

Download molding design files

Fabrication parts

Once you have the molds, you have to enter them in V-Carve and prepare the file for 3D, or 2.5D, machining. For this, it is first necessary to enter the measurements of the material to be used, which in this case the measurements of each mold coincide with the wax block to be used, machining only the inner part.

For preparing well what we are going to mill, is important to know which end-mill are we going to use. We have to take in account its Diameter (for letting some space between part zones, bigger than the diameter, where end-mill needs to pass) and its Cutting Depth (obviously, it cannot go down and cut over this distance). I am going to use a 3-6-12 end mill: diameter 3 mm and Cutting Depht 12 mm.

And after that, I exported it in STL format to go to Vcarve software. As in the exercise 08 I used this software for machining, but in this case I used it with Roland MX40 machine. I imported 3D model (in STL format):

And then I put it in the correct position and orientation. I put the size of the mold because it is the same of the part that I am going to machine. Then, if we go to Drawing view, we can see in grey code what and how deep is going to mill the machine: the more black the deeper. Using this view, move the model near our (x,y) origin.

I use Vcarve 3D Toolpahts. First of all 3D Rough Toolpath, to remove most of the materialand the finish surfaces using 3D Finish Toolpath.

Configure tool trajectories with the meassures of me part.

And select the tool for milling, in this case, as I say before, 3mm end-mill: I do the samen with the two trayectories.

I created in this way two machining works: Rough and Finish. For the Finish I configured it in 45 degrees. The best way is to do two finishing millings, one with 45 degrees angle, and the other with -45 degrees angle, but this first time I did only one. I did not need a fine surface; it is an internal part, not visible and aesthetics. Once I had these trajectories, I realize that if I have done the 3D model only for the surfaces I had to machine, and not with dimensions of the entire block, it would be a faster work, so I redesign the 3D model, and I repeated the process with it.

And yes! First of it, theoretical times were about an hour, now they were about theoretical 15 minutes. (See image below). You can download Reduced 3D model here. In Save Tool Trajectories

Download molding fabrication files

Final result

Then you just have to join the parts of each mold and press with some clamps so that they do not open. Then we have to calculate the volume we need and prepare the mixture of the material that we are going to pour, as previously mentioned, a blue Ferris File-A-Wax silicone with its catalyst. Once the mixture is done, you just have to pour it into the mold and wait the indicated time until it dries. In this case, a minimum of 6 hours of drying is recommended. Then you just have to open the mold and carefully extract each piece, it is very important to apply a release fluid before casting the material to facilitate this task.

Being made in 2 parts, I have had to join it using an epoxy that dries in the sun and is totally transparent. It also helps fix blemishes. Below you can see the final result of the molded the surf quilha, now they are available to go sufing with them.

Exercises

Exercise 17:Wildcard..

In the following exercise, it was decided to use the embroidery machine, it is a machine that recently arrived at FabLAB, it had not been configured. This assignment will be used to learn how it works and to start using it in the FabLAB. For this exercise it has been decided to embroider the Deusto FabLAB logo in color.

Prepare Design

First, you have to prepare the design in vector format and save it in color EPS format. For this, the Illustrator software has been used, with which we have worked in the rest of the exercises. As stated at the beginning, the Deusto FabLAB color logo has been used.

Download design files

Once the design is prepared, it is opened with the Digitizer embroidery software, which is ready to configure the type of embroidery and modify the designs. The steps in the following manual have been followed since it is the first time it is used. In this case the design will not be modified, only the color and type of embroidery will be assigned, which in this case will be "satin", which is the one that is predefined since it is the first test.

Download software manual files

You also have to select the right hoop that will depend on the garment and the size of embroidery you want to do. When entering it, you have to select the machine and adjust the design to the size and orientation desired. Once placed, the stitch variables mentioned above and the type of thread used are selected. Before taking a file for the machine, you can give "true view" to preview how the embroidery will look. If everything looks correct, you have to extract the design in ".dst" format and save it on a flash drive so that the machine can read it.

Download machine embroidery files

Embroidery

The machine used is an ELNA Expressive 830 automatic embroidery machine. In order to place the needle, the thread and the frame, the instructions in the user guide of the machine itself have been followed, so that it is configured to launch the design once the frame is on the rack, and this is placed on the machine.

Download machine manual files

The rack selected in the Digitalizer software must be used and positioned in the same way. For this, the garment must be fixed to the frame with the clips included and seen in the image, placing a support on the back or stabilizing it, which will help the embroidery to be more precise and the fabric not wrinkle.

When the machine is spinning, is recomended to locked for safety and it´s moment to put the frame with in the machine..

Then you just have to mount the frame on the machine and launch the previously loaded design, for that you have to have the green GO button on the machine. When a color is finished, the machine stops and asks you to change the thread, you do it and you give GO again; so consecutively.n

Once outside, it is turned over and the remaining thread and support material are trimmed, so that it is as clean as possible. Then it is possible to remove the gown from the frame.n

Result

Below you can see the final result of the Deusto FabLAB logo embroidered on one of the lab coats. The result has been satisfactory and we will proceed to embroider the rest.

Exercises

Exercise 18: Mechanic Design

Given the situation of the COVID-19, this year the construction and testing of the machine has been complicated. As we cannot move around Spain, we have decided to manufacture the machine in León and some components of the team will help remotely.

Team

In this machine the working group is formed by Alvaro Macian (Cartagena), Lola Ojados (Cartagena), Adrian Torres(Leon) and myself.

Inspiration

During the machine choice debate on Thursday, we decided to use Jake's modules, drawing inspiration from the work done by Pablo Nuñez, Epifanio Lorenzo, Yuichi Tamiya, Apeksha Bochare, Pradnya Shindekar at the Bootcamp in Kerala (India). An image of the videoconference, showing where the documentation is and how the machine will be.

Design

Thanks to the documentation of the instructor of Leon Pablo Nuñez and the Jake Read repository, we begin to design the machine. In this case we are going to create a machine with two X and Y axes, like a plotter, in which the end effector can be something to paint. Jake's modules are easy to manufacture because you only need three parts of the structure cut with the laser and assembled with small 3D printed parts. In Kerala they designed some legs, so that the module can be supported. In our case, this is the layout of the machine. Thanks to David Prieto (Fab Lab BCN), for converting the original Jake's from Rhinoceros 6 file to Rhinoceros 4.

Modify the part of the slider, so that it can be connected to another module. The green piece is Jake's original, the gray is the modified one. By making an inventory of the necessary parts in the Fab Lab León, we realize that we do not have the appropriate size bearings or the necessary inserts. We try to buy them, but they don't sell them in León. So it's time to change the plans. This only affects the structure, but not our mechanism, the change is the substitution of some materials or mechanical parts for others, but it does not affect the tool holder designed by Iván or Álvaro’s programming..

Thank goodness that during the choice of the machine, we had an option B. And they are the use of Nadya Peek's modules. For several years the students of the Fab Academy of the Fab Lab León have used these modules. For the creation of the X and Y axes to create a plotter, we were inspired by the machine they made at the Fab Lab Facens in 2017. Thanks to Nadya Peek's MTM page, you can download the module designs. Also thanks to the documentation of the "Cintya" machine made by the Fab Lab León in 2019, I begin to design the different modules. A module for the X axis, a module for the Y axis with a union connector for both axes.

To design the tool holder, two heads have been thought to give it stability, they have been designed to be the same and they are mounted upside down. This is attached to the mobile support of the mechanism and has a spring-like design to allow some flexibility in the event of a collision. In addition, the hole has been designed in such a way that it enters all types of markers and is tied by means of a screw that pushes the screw against 2 wedge-shaped walls. The piece has been thought to be made in 3D printing. As will be seen later, the design of the structure of the machine had to be changed and 2 do not fit, so only one has been placed because it has been verified that it can also work.

As the Y axis a part is in the air, to give it a mobile foothold, I design a marble holder inspired by the educational robot "Escornabot". Ivan sent me the design of the end effector, a holder to hold a pencil or a marker and we add it to the simulation.n

Fabrication&Assembly

Once the simulation was done, we went on to create the exploded view of the machine to cut it in the laser and the support with the marble holder that will be 3D printed. At the bottom of the page you will find the files to download.

The machine requires 3mm DM, two stepper motors with calibrated rod, four 9.5mm aluminum cylindrical guides, a PLA or PETG filament and two marbles. The first thing we will do is cut all the pieces with the laser cutter. The Fab Lab León laser cutter is 600 x 300 mm, so we have to use two 3 mm DM plates. The cutting parameters are Power: 90% / Speed: 15% / Frequency: 5000 Hz ppi 400

At the same time we print on PETG the supports with the marbles and the support of the tool that Ivan designed. The marble support, we put supports so that it makes perfect the accommodation of the marble. And this is the result of the movement of the marble, inside the support. It rolls and also has some slack to give us cushioning.

The next step is to assemble the Nadya modules cut with the laser and screw the steppers. To join the laser cut pieces, although they have pressfit, some pieces we assure with hot silicone and white glue. Make sure that the calibrated stepper rods fit snugly into the plastic inserts.

The next thing is to mount the support with the marble on the end of the machine and the support of the tool that Ivan designed (we have to say that we made a mistake and mounted the opposite axis, nothing that cannot be solved by changing it in a moment). And this is the end result of the machine.

Electronics connections

These are the electromechanical components that we have used in our machine. We do not have information about the rod because it is recycled from another project. Based on information from similar rods we initially consider the feed to be 8mm / turn.

Programming

As we have little time, we will use a firmware to control the machine. In this link there is a list of the most used firmwares for 3D printers and CNC machines.

We decided to test the GRBL firmware because it is easy to configure and can be controlled using the Universal G Code Sender software. To download the Universal G Code Sender software, click on this link. To run it you need to have JAVA installed.

We downloaded GRBL firmware from here.

We cannot install it because it is an update of the previous version and it needs you to have the first version loaded on the arduino, so we find this link to download it.

In examples is the script to load the GRBL to arduino.

We try to program with arduino IDE and UNO using windows and a Ramps board. After several attempts we could not get it to work due to a problem with the system library, among others. We had to change equipment and software to get it working.

We load the script into the Arduino Mega without connecting the Ramps for security. Now we open the Universal G Code Sender to try to move the motors.

We connect to the Arduino Port and in the “Machine Control” tab we try to move the motors by pressing x +, x-, y +, y-. But the motors do not move with this firmware. Maybe we have to modify the code to work with the ramps. We looked for solutions to my problem and found that there is a GRBL firmware version for Arduino Mega and Ramps. This is the link. we load it into the Arduino without any problem.

But when Adrián and Iván try to load it, appears an compilation error. Cannot find the system.h file. Finally, Adrián tries another computer (Nuria’s super computer) and manages to load the firmware on the Arduino. We connect the Ramps (with the drivers and motors connected) to the Arduino and connect the power supply.

Now we open the Universal Gcode Sender. And we select the Arduino port, 115200 baud and GRBL. We click on “Open” and the software connects to the arduino.

To do a first test, in the “Machine Control” tab select “Step Size” = 10, “millimeters” and click the x +, x-, y +, y-, z + and z- buttons to move the motors.

The next step is to correctly configure the firmware so that the car moves the distance that we say. In the “Commands” tab, we write “$$” to see the parameters. But the carriage moves 24mm instead of 40mm. So we make a cross multiply and we get 416 steps/mm.

The relationship between motor steps and displacement in millimeters (steps/mm) of each motor are the parameters 100, 101 and 102.

CAs we do not have the datasheet of the threaded rod and the motors, we have initially considered the following parameters: Threaded rod feed = 8mm / turn; Stepper feed = 200 steps/ turn ; So 200/8 = 25 steps/mm. We change the parameters writing in the console of the “Commands” tab. We tried moving the carriage 40mm using the buttons on the “Machine Control” tab but the carriage barely moved

Rod and motor parameters are not correct, so we have to test values to correct it. We tried to configure to 250 steps/mm. But the carriage moves 24mm instead of 40mm. So we make a cross multiply and we get 416 steps / mm. Now the carriage moves what we say

Sending G-Code

Universal Gcode Sender software allows you to use a gcode to move the machine.

We tried using Mods to generate a gcode and loaded it. But it doesn’t work properly. In addition we realize that we have interchanged the z and y axis. We changed them on the ramps to fix it. But that gcode keeps doing weird things. So I use Cut2D / Aspire software, which we normally use to generate gcodes for my circuit mill.

Finally we open this gcode in Universal Gcode Sender and it works correctly.

Final result

Now we can lounch the design and the machine is going to start drawing.

The machine was manufactured and configured in less than a week. It is something incredible, given the situation. But if we had more time, we would like to improve the end-effector. we would use a rack and pinion to raise and lower the marker and that would not mark the page, when it makes the trajectory in the air. we would also like to try using other tools, apart from the marker. Same as using a litter box and moving the sand with an awl, or marking the modeling clay.

Download mechanic design files

Given the situation and the moment we are going through all over the world, we am very proud of this team. Thanks to videoconferencing and in real time, we have managed to assemble a machine, program it and have it draw something through a GCODE. It has been incredible; guys when all this happens and we can meet, we have to take a few beers to the health of the machine, LE-CAR-BIL.

Exercises

Exercise 19: Project development

In this exercise, I explain the learning obtained during the final project, evaluating the different tasks and their degree of completion.

What tasks have been completed, what tasks remain?

The project has been successfully completed and all the tasks have been completed to make the scooter I designed work. A product has been designed that can be parameterized to fit any conventional scooter, respecting the criteria of circular economy and empowerment of technologies defined in the initial objectives. All the components have also been manufactured using the different technologies required, a PCB has been designed to control the motor of the scooter with the throttle together with its programming and finally assemble everything until I can make it work. Due to the current situation generated by COVID in which we have been confined and I have not had access to the LAB to develop the project for several months, it has been impossible for me to finish in August 2020, which is when I had planned. This interruption affected the result, not being able to develop the project as much as I would have liked, especially in the manufacturing and electronics.

What has worked? What hasn't?

The scooter works correctly, but if you accelerate too much the belt may slip on the wheel pulley. Perhaps the throttle's acceleration curve should be adjusted so that it accelerates at a slower pace and also reduces top speed. You could also use a belt with larger teeth or try to couple the motor directly to the wheel. Although I managed to make the scooter work, it broke half after using it for a while, probably due to the weight and the fact that the wood used (DM) is not rigid enough to support the weight of an adult. Some 3D printed parts have also been broken, some electronic components have also come loose and the PCB has been damaged.

What questions need to be resolved?

I have not had any problems in the mechanical design and manufacturing part, since they are knowledge that I already had from my training and I only had to put them into practice for this project. I would have liked to develop the design a little more, but the confinement situation has meant that part of the work can not be done almost to the end, because I did not have the electronic components until the end. As I had to develop the electronics part on my own from home and not have the means, it was very difficult for me to make the selection of components and understand how I had to design the PCB to be able to control the motor with the throttle, in addition to the components ordered through the internet it will take a long time to arrive due to the current situation. Luckily I had the help of my local instructor, for once the components arrived, I understood well the steps to be taken and satisfactorily developed the electronic part.

What will happen when?

If you want to continue developing this project, you should stiffen the scooter, perhaps with a more rigid material (Natural wood, multilayer, methacrylate ...) or even use metal profiles. It would also be advisable to adjust the throttle curve to make it slower and improve the traction system to prevent it from slipping.

What have you learned?

In my case, I learned a lot about digital manufacturing technologies, I came from the manufacturing industry in which other types of machines and materials are used. For example, how to design the settings so that the parts can be assembled, taking into account the contraction of the 3D printed parts or the material subtracted by the laser cutting machine that must be taken into account for the pressfit. But actually where I have learned the most is with electronics and programming, I had almost no knowledge about this and before doing the Fabacademy I was a little scared because I thought you needed to know a lot to do this kind of thing. I know that I still have a lot to learn and that I have only approached an immense area of knowledge, but this motivates me to continue learning and each being more capable of contributing in the electronic part in the projects in which I work and will work.

Exercises

My project

Fab Academy 2020 has already started and therefore it is time to launch the final project, 100% DIY. Here you can see where the idea comes from, how it has evolved in each of the stages and step by step to manufacture the final product.

As explained in the first exercise (Principles and practices), it has been decided to manufacture an electric scooter. The challenge is to recover a scooter that is in disuse because it is damaged, motorizing it and manufacturing all the components designed internally for this purpose.

Management

Although this planning may undergo modifications, it is important to do it as soon as possible, otherwise the project will not progress progressively and will eventually expand over time.

Analysis

Before designing anything, it is essential to analyze the product, the market and the user well. Then a benchmark will be carried out to see the specifications that the product should have depending on the competition. Second, an aesthetic analysis will be carried out to define the formal codes that the design must follow to please the user.

Benchmarking

In this section we have gathered a comparison of the different electric scooters that can be found in the market. The objective is to identify minimum specifications that must comply with the prototype, so that they work similarly to a commercial product.

It is very important that during the design special attention be paid to the selection of the electrical components, especially that of the battery and the motor. To ensure that the scooter moves at an adequate speed and has acceptable autonomy, it is necessary to take into account the weight and power of these components.

For the battery, a lithium model has been chosen, since they are used in the market scooters because of their low weight and high performance. As for the motor, it is advisable to use a brushless, since it has a good relationship between the torque, maintaining a low consumption and being easy to install due to its low weight and dimensions. The engine will transmit with a belt the movement to the wheel instead of with a chain or a direct coupling, since it is the most economical option and of easy installation.

To control the speed, know the state of the battery and be able to activate other functions (Light and sound), it is planned to incorporate a display on the handlebar to display this information and some controls to interact with the vehicle. It is important that the scooter has a brake and although sometimes it is motorized (drum or disc), in this case it has been decided to keep the original brake that is activated by pressing with the foot the piece that will make friction with the wheel.

It is possible that during the course of the project some components that have not been foreseen as the damping are incorporated, everything will depend on the real need to incorporate them and the complexity of their installation to finish the project on time.

Other projects carried out in the different FabLab of the world in search of inspiration have also been analyzed. On the one hand, we want to identify the outstanding projects to avoid falling into plagiarism and on the other hand, ideas are going to be taken to apply my project.

I have not found any electric scooter project that starts from an old product, so it seems a good starting point for the project. Some concepts that can be applied to the product have also been identified, such as the possibility of manufacturing rubber wheels with molds and the most efficient way to motorize it; which in this case seems to be a brushless motor that moves the rear wheel by means of a pulley and connects to a Lithium battery.

Moodboard

The formal design and aesthetic codes of a product are very important for a product to be attractive and invite to use it. In fact, the design must communicate the function for which it is designed. In this case we have opted for an aesthetic that provides a certain image of speed and robustness, since it is a vehicle and both are features to highlight in this type of products.

As you can see in the moodboard, the design is composed by inclined planes that provide a differentiating character, a perception of stiffness and an image of aerodynamics, which is maximized by highlighting the joints between surfaces that go in the direction of movement. In order to reduce the aggressivity of the design and provide the elegance, the composition of the plans should be mostly symmetrical and without major changes or sharp edges.

All these components must be housed inside the scooter and have to be as integrated as possible, for that part of the structure of the original product will be maintained and the necessary parts will be manufactured.

Brief

The objective of the project is to achieve an attractive product that works according to market standards. After performing an analysis of the different aspects of the product, the following specifications have been defined. These are not data that must be strictly complied with, it is an approximation to choose the appropriate electrical components.

In the following stages a study of the current product and a selection of the components will be carried out, with the objective of conceptualizing the solution in the greatest possible detail and preparing all the technical documentation for its manufacture. It has been defined as an objective that the project be as sustainable as possible and for this reason, the selection of components and materials should have the least possible ecological footprint, proposing a design that generates the least possible residue, reusing existing products that are obsolete and using recycled materials.

Conceptualization

Below is the initial sketch of the idea, starting with a broken scooter and identifying which parts to design and manufacture.

In the first place, the water scooter has been modeled in 3D and then the way of assembling the electronic and mechanical components has been analyzed, in addition to adapting the measurements for an adult user. In the following image you can see how the skateboard is used and how the final design will look.

Developtment

The design has respected some parts of the original skateboard so that the product is as sustainable as possible, since the objective is to recover a skate that is not used or is broken, to turn it into a personal electric scooter. To do this, first the original product has been disassembled and all the parts have been measured to make the 3D.

Mechanic part

The base of the scooter has had to be cut to fit all the components (Board, motor, battery ...) and a sandwich system has been designed with several pieces to close and join everything with M6 screws.

Then the rest of the pieces that have to be manufactured for the electric scooter to work have been designed and modeled; in addition to the components to be added (Board, battery, motor ...). For this, Solid Wors has been used, first each piece has been modeled and then they have been assembled. Once all the pieces fit together, the different manufacturing files have been prepared. In the following image you can see the assembled and exploded design with the parts list.

At the bottom will be the housings printed in plastic on the 3D machines, divided into 3 parts due to the size of the machines available. In these housings the battery, the electronic boards and the motor will be placed successively.

Then there will be the 2 parts of the base of the scooter that has been cut and on top of them 2 pieces of 22mm wood to cover the upper part and generate a base to get on the scooter. On top of this, a laser cut sandpaper will be placed to ensure better adherence when skating.

For the motor transmission,a 3D printed part has been designed that attaches to the rear wheel and has a pulley to connect to the motor with a toothed belt. In this case there is no brake, the original manual system is maintained.

Here you can see the final design of the scooter with a render that shows the result, as well as a video that helps to understand how it is assembled.

Electronic part

Here's how the electronics of the skateboard work and how you have to make the connections to make them work properly. The design has an AC motor, a Lithium battery, a throttle to accelerate and a controller to adjust the voltage awith a BEC incorporated to convert the signal of the battery in 5V for the processor adn the throttle. It also has a battery charger that is not on the skateboard and is only used to charge the battery, so the battery that can be disconnected from the engine has and connected to the charger.

To operate the scooter, it is necessary to transform direct current of the battery to alternating current to operate the motor, using a 10-cell (10s) variator that will serve to capture the analog signal collected by the throttle and send it corrected by the program loaded in the processor.

After having defined the electronic schematic, it has been drawn in Eagle. The design contains an ATtiny44 processor and four 4x4 connectors, which will serve to connect the different components. The board contains a line for the voltage (Vc) to feed the processor and the throttle, another for the ground and a last one for the signal that goes from the throttle to the motor, passing through the processor and the variator (ESC). Once the scheme is drawn, the plate is prepared to be able to manufacture and assemble it later. Is importan to use the analog pin for the throtlle and one in with PWM for the ESC conversor.

The board that we have to manufacture has an ATtiny44 processor and 3 output pins that will go to the throlle to change the speed of rotation and the other to the motor passing through the controller that will transform this signal so that the motor starts working with the load of Battery. First, the scheme has been drawn in Eagle and the image (.png) of the plate that we want to machine has been obtained.

Manufacturing

Once the mechanical and electronic design is finished, it is time to start manufacturing the different parts using the appropriate manufacturing technique for each material. First of all, 3D printing has been used, then CNC cutting and finally laser. The steps followed in each case are explained below.

3D Printing

For the pieces of plastic material, FDM printing technology has been used, which offers results with sufficient quality for this type of project. In total 3 housings, 2 pulleys and a piece for the handlebar have been printed. The machine used was the BCN3D Sigma + with Cura software. A 0.4 nozzle and a 0.2 layer height have been used, sufficient for the desired quality and with a not too long printing time; the rest of the values are pre-defined for PLA.

Once the pieces were printed, the support material has been carefully removed and small imperfections have been repaired by sanding them, ensuring that the pieces fit well and have a good appearance.

CNC Machining

For the wooden pieces, the large-size CNC milling machine that we have at FabLAB has been used and the wood chosen was 22mm DM, in order to take advantage of the excess material and not start a new plate, it is also believed that it can work well and It's not too heavy. To prepare the machining files, the V-Carve software has been used and all the toolpaths have been prepared. In this case the 2 pieces have similar trajectories; first a 6mm holes with a 3mm tool, then a 3D recess to shape the inclined planes with the same tool and finally the cut that allows removing the piece, on the one hand the internal and on the other the external.

Once the files have been prepared, they have been introduced into the machine, the material has been placed, the part origin has been defined and the 2 parts have started to be machined. Once finished, the corners have been cleaned and sanded to leave a better finish.

Laser

The laser cutting machine is going to be used to cut the grip of the skate, it is a sheet with sandpaper on the upper part and a surface with glue on the lower part (which allows it to be glued to the board). This piece allows the sole of the shoes not to slip when riding the scooter, which could be dangerous. In addition, we wanted to customize this sandpaper so that it has a unique aesthetic, in this case a pattern has been drawn and the name of the product has been written (Re-Vive) and elements that make references to Fabacdemy have been added (Logo and school year).

In order to cut and engrave the grip, the design has first been prepared in Rhinoceros, grouping each type of operation into the corresponding layers (cut in red, partial cut in green and engraved in blue). Once the design is finished, you just have to go to the machine and launch each path separately, as it is a material that I had never cut, first I did some tests to define the appropriate values ​​(Cut = S10 P80, Partial Cut = S60 P20, Engraving = S60 P40). To launch each operation, you have to enter the print menu, center the object on the work table and press to print so that the machine works. As it is a surface that deforms and does not remain flat, it is going to work on a wood on which the grip will be nailed; once prepared, you can focus and start cutting.

PCB

Now is time to make the boardusing the CNC machinning converting to BMP from PNG, important being defined by bitmap. The same copper board and milling machine has been used to manufacture it as in the other electronics assignments, using DR Engrave and Vpanel to communicate with the milling machine. I use a stepover of 0,1mm and a milling width of 0.15mm in engrave and 0,35 in cutting, with a conic mill to do the engrave and a cylindrical for the outer cut, booth with a diameter of . By introducing the generated image in Eagle, the manufacturing file is prepared in DR Engrave and machining begins.

Then you have to clean and assemble the components, in this case the ATtiny 44 processor and the 3 connected with 4 pins each. Once all the components have been soldered, you can start to assemble the electronic components and test their operation before mounting them on the skateboard.

Programming

The program is created using Arduino software and then loaded into the previously manufactured ATtiny processor. This program regulates the speed of the motor with the analog signal of the throttle from 0% to 100% and tranforming to dgital from 0bit to 1023bit fot the ESC variator. The motr will read from 0 degrees to 180 degrees. The program needs to communicate through the analog pins that are used to communicate the throttle with motor through the ESC . This porgram is enough to make the scooter work, it can also be edited if you want to make changes in the speed in the case that 100% is too fast..

Once the program has been designed, it is time to load it onto our board using the FABISP program loader from exercise 5. The program has been loaded correctly, so the next step is to connect all the electronic components to the scooter to finish the product. and be able to start using it. Before final assembly, it has been assembled separately for testing to ensure it works.

Assembly

When all the parts are manufactured and the electronic components connected, it is time to start assembling the scooter by following the steps followed when disassembling and adding the new parts in the corresponding order. I have paint some parts in black toincrease the aesthetics.

First of all mount the throttle in he handelbar a pass wire from the inside of this part to communicate with the board. Then take the battery, the motor and the rest of the electronic components mand assembly inside the plastic housings.

To finish take the screw of M4 and nut and fix then. Now we just have to stick the sandpaper and paint the pieces we want if we want to customize the aesthetics, in my case it will be all in black since it gives a more serious look and makes it look like a more compact product.

To finish the assembly is necesary to probe if the motor work correctly and transmit the speed to the wheel. For this is necessary to connect the battery and put the tap to covert the electronic. Now moving the throttlethe system start working and the wheel moving, as is shwn in the image.

Here you can see how is the scooter after the assembly, now is time to use it.

Final result

Below you can see the final result of the project, in which a scooter was used that was going to be thrown away in order to avoid waste and have a more innovative product. In total, few pieces have been manufactured, since many are from the original product, this makes its environmental impact is the minimum in comparison with a fully designed product. The result is satisfactory despite the fact that improvements can be made, such as an indicator of the battery status or some type of lighting that characterizes the product.

The following video is a summari of the work done on the project, going through the design, ideation and development phases. By following the steps you can also give to your skate a second life.

To finish I leave here the folder that contains all the files. On the one hand there is the 3D file with all the components, the electronics diagram, all the manufacturing files (CNC. Laser, 3D printing, PCB ...) and the program to load into the microcontroller.

Download final project files

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