[Electronics Design]-
Tasks for the week:
This week assignment-
1-Redesign echo hello-world board in any PCB design software and interface a button and LED to ATiny44.
2-Check the design rules, make it, and test it.
Learning PCB design Software - Eagle
I am fest time using eagle software so I am learning basic command,design and all the things.
What is Eagle
EAGLE stands for Easily Applicable Graphical Layout Editor (German: Einfach Anzuwendender Grafischer Layout-Editor) and is developed by CadSoft Computer GmbH. Cad soft Computer GmbH was acquired by Autodesk Inc. in 2017.
EAGLE contains a schematic editor, for designing circuit diagrams. Parts can be placed on many sheets and connected together through ports. The PCB layout editor allows back annotation to the schematic and auto-routing to automatically connect traces based on the connections defined in the schematic.
{Download, Install, Run}-
EAGLE is available on Cad software (the developer company) download page. EAGLE installs just like any old program, install self extract and then present you with a series of dialogs to configure the installation.
There are 2 main steps in designing a PCB in Eagle.
1. Design Schematic - In this section we can add components our PCB and specify the connection between them. we can also add the values of componenets.
2. Design Track- Here I started designing of my circuit board. 1. Open the eagle then click on the new project and save your project name for Example "hello board". Then select the schematic section.
Adding library-
After download and installation of Eagle, I realized that I need a components library to find the components we need for our design. So, I downloaded the fab.lbr from here. Then I saved the fab.lbr to the right libraries file folder (In my case: C:\EAGLE 8.6.0\lbr) & did settings in Eagle to use the fab library.
Open the eagle then click on the new project and save your project name for Example "hello board". Then select the schematic section.
Download the fab library (components) and add it to eagle library. For this type "use" in command line of schematic section and search the folder in which you dowanload the fab library and open it.
After this you have add the component for your PCB. For this type "add" in command line of schematic section and find the fab library.
Here You can add all components which you want for PCB. I added resister, capacitor, connectors and Attiny44. For my hello board I added a LED with limiting resistor and a switch.
So, all components are in schematic section and its time to connect them. You have make grid visible for better accuracy of connections. Go to view--->grid---> and turn on the display. Make settings (size: 0.05).
Now I connected all components by using net(green). If two wires connected in a diagram, they are shown with a dot at the intersection.
Here I learn forward voltage and amps.
I read about the Data Sheet I Attiny 44 operating system.
Adding components
Then I started making the schematic of echo hello-world board. I prepared the list of components needed for making echo hello-world board as follows :
Electronic Components for Hello world board
-ATTINY44-SSU x 1 - Micro controller
-LEDFAB1206 x 1 - LED
-CAP-US1206FAB x 1 - Capacitor
-RES-US1206FAB / 49k x 1 - Resistor
RES-US1206FAB / 10K x 2 - Resistor
-FTDI-SMD-HEADER / 1X06SMD x 1 - FTDI header
-6MM_SWITCH x 1 - Switch
-RESONATOR - Crystal oscillator
-AVRISPSMD / 2X03SMD x 1 - Header 2X3
I added all the components in schematic sheet by using add menu & selecting required components from FAB library.
Connecting the components
There are two was to connect components in a schematic:
You can connect the components with a wire (also called a "net" in Eagle). This may make connections obvious at first, but can get really messy quickly as nets cross over each other.
You can also name the nets attached to components that need to be connected by naming them with the same name. See example schematic above. Eagle will ask you if you want them to be connected. (Say yes!). After you name the component - label it so the name appears in the diagram.
I used both methods for connecting the components.I used label command to show the name of each net to make the schematic readable.
Here is the final schematic with the button and LED added:-
Adding LED & Button
I added a button and an LED to the design. When adding the LED, I made sure to put it in series with a current-limiting resistor. To estimate the resistance required, I considered using a red LED, which has a voltage drop of about 1.8 volts. With a desired current of 5 mA (approx) through the LED, a (5 V - 1.8 V)/(5 mA) = 640 Ohm resistor is required. So, I decided to use 499 ohm resistor (because 460 ohm resistor was not available.
When adding the button, I decided to use a pull-up resistor configuration. Essentially, the microcontroller’sinput should always be driven high or low, and using a pull-up or pull-down resistor with the button is a way to achieve that. I chose to use a 10k Ohm resistor. To understand the basics of pull up or pull down resistor,
I decided to connect LED to PA7 & button to PA3.
Routing the traces on the board
Then I swiched to board layout view. The components I had added were jumbled up in a corner with yellow unrated traces attached.
I used move command to arrange the components at proper place.
By mistake selected wrong package
Fest time i used auto routing command
And next Step-
For routing, I used manual route command. After few trials, I managed to generate layout as shown below:
Next step
Exporting board layout to be used with milling machine
Eagle can export PNG images of PCB. I just needed to disable all the other layers but Top layer in View > Layer Settings, so that I could get a clean image.
I exported an image at 1000 dpi. Here is the final result:
Then I milled this image on copper clad by using the method we learned in Week 4. But the milling failed because distance between any two tracks was too less to mill it using 1/64 inch endmill. Then I went through the websites of previous FAB LAB students to find the solution of this problem. And, I came to know that for proper milling I should use the proper design rules.
Bit details:-
We used 1/64 inch endmill. 1/64 = 15.625 mils. we should use a clearance of AT LEAST 16 mils. 17 or 18 is probably safer. Hencr, I downloaded 17 mils DRU file fablab_17mils.dru
Then I repeated the steps of auto-routing & exporting board layout as .png Image. Here is the final result.
Creating board outline:
I created the board outline in milling layer. I kept the width slightly greater than that of the copper layers. Then I make TOP layer OFF & exported the outline as png image (monochrome).
Bit details:-
We used 1/64 inch endmill. 1/64 = 15.625 mils. we should use a clearance of AT LEAST 16 mils. 17 or 18 is probably safer. Hencr, I downloaded 17 mils DRU file fablab_17mils.dru
Then I repeated the steps of auto-routing & exporting board layout as .png Image. Here is the final result.
Creating board outline:
I created the board outline in milling layer. I kept the width slightly greater than that of the copper layers. Then I make TOP layer OFF & exported the outline as png image (monochrome).
PNG Image: |
|
PCB Milling Machine Modela MDX20
Characterize the PCB Machine
Software: For Controlling and giving command on Modela MDX20 we are using Fab Module from Linux system
Hardware: I'm using Roland MDX20 Modela for my PCB making, which has Working area 203.2 x 152.4 mm within the dimension around 476 x 381 x 305 mm, Z stroke is 60.5; Spindle motor 10W DC motor; spindle speed 6500 rpm.
PCB Placing:
For placing PCB board on on the Modela working area, first I used foam tape than attached 3mm acrylic sheet. On acrylic sheet I placed the PCB board by double sided tape tightly.Then I tested around the PCB is it fixed or not.
Fab Module
PCB milling using Fab module.
Modella MDX 20 behaves like an ordinary 3-Axis CNC machines, Each axis is driven by a stepper motor and the cutting program tells the machine where to go by giving coordinates to the machine in real time. What the software does is that it converts the .png image we give into a series of tool paths, these tool paths are defined by their coordinates. The .png image is a black and white layout of the board, and the black portions will be milled and the white portion is where the copper will be left.
Got to the terminal and run fab Now the fab module will open and the select the input format to .png and select the output you want depending on your machine (modlella MDX 20). On the top menu select the process you want to use. For milling traces, select the milltraces(1/64) option. Now click load .png to load your traces file and click make path Now you can see the path the tool is going to move through. You can change the setting, I'm leaving it in the defaults. Now if you click make.rml and click send rml
ENDMILL - 1/64" i.e. 0.4mm is used for traces the board and 1/32" i.e 0.8mm is used for cut the board. We have to fix the end mill with the help of allen key.
Milling the PCB
During milling, I faced two problems -
1-Outline milling layer problem.
 |
2-The tracks for the IC were not milled properly
|
Second Time new design and milling
|
Next
|
Components-
Next after solding
Finally, I milled the board using FAB Modules & MDX-20 milling machine & soldered the components. While milling the outline, I inverted the image in FAB Modules.
Gorp assignment:-
The group assignment for this week was to check various tools, which display numerous properties about electrical components.
Description:-
The basic oscilloscope, as shown in the illustration, is typically divided into four sections: the display, vertical controls, horizontal controls and trigger controls. The display is usually a CRT (historically) or LCD panel which is laid out with both horizontal and vertical reference lines referred to as the graticule. CRT displays are additionally equipped with three controls: focus, intensity, and beam finder.
|
|
|
Hello board test and signal test in oscilloscope |
Here we are learning about oscilloscope and how to check components and Frequency-:
