Electronics Design

My experience

First step

Remembering week 4 of the Fab Academy (click here), thanks to those first explorations and those first investigations about the beginning or the basis of electronics I was able to have a better understanding of this process, this week we are asked to design our own board, solder it and program it. The steps to do it are many but the first thing you must have is the necessary components and the tools you are going to use, here is the list that I needed for my first test: ✔️

Components:

1. USB
2. Zócalos
3. ATtiny85
4. Res68 ohms
5. Res270ohms
6. Leds
7. Boton
8. Baquelita

Tools:

1. Cautin
2. Estaño
3. Pinzas
4. Pasta de soldar
4. Desoldador

What I got

Here in Lima I was able to get the necessary components in a store in the center of the city, they are not so cheap but not so expensive either. Thanks to my partner Hayashi Mateo we made a single purchase to avoid going several times so it is advisable in a pandemic context to avoid going out the least amount of times to get anything. In total I spent an average of 40 soles for all my kit for this assignment. 😃

Exploring

Thanks to the support of a classmate's parents we got to know an old oscilloscope, I had never seen one before and even less such a big one, it was very interesting to know how it works and how to manipulate it, unfortunately we could not complete our task because something was wrong with its operation, but it was still a nice experience.


In the lab we got together to make an oscilloscope. An oscilloscope is an electronic display instrument for the graphical representation of electrical signals that can vary over time. It is widely used in signal electronics, often in conjunction with a spectrum analyzer. Thanks to our colleague Hayashi Mateo who is an Mechatronics engineer we were able to solve the assignment together, the only thing we needed was an ARDUINO UNO and a laptop to be able to do the test, the only restriction was that it could only recognize up to 5 volts, anyway it was interesting to see how we can solve something in a homemade way despite not having a machine. 👏

Working

As a first step I needed an arduino nano, some jumpers, my board and the help of my mother and my sister, they supported me in holding the wires to show the video you will see below. 🥰





To get that graphic on the screen I used the Arduino ISP, this is a program that you can download from the official Arduino website. (click here) The arduino ID has 3 parts, global part (sensor), void setup (pins - serial) and void loop (functions that are going to be repeated). As I need communication between my display and the arduino nano I activate the serial function, bi-directional communication, then I used a code in the three parts that I will show in the pictures.



Finally as we already have our program ready to respond I place two jumpers, together the negative with the GND of the arduino and the positive with the A0, this to respond our graph, then you can see how the figures change on our screen, it was very interesting to know this whole process and above all make it real. 💪🥰

First attempt

In my case, since I already had my first board soldered, I used it to test the programming. The first thing is to get the USB input to solder it together with the pins and connect them, here I show the images of this process. 🙂


As a next step I needed to test that there was no short, otherwise it could be detrimental to my laptop usb port. For this I had to create a kind of tester, I don't have a multimeter at home so I made one myself. To build a tester you only need a led, a resistor, two wires (negative and positive) and a source, in my case I recycled an old cell phone charger and soldered it. This allowed me to foresee any inconvenience in my board, below I show what happened.

Second attempt

The result was not good, 😢 my board was shorting out, this needed to be repaired before any further steps. At first glance my soldering was not good and since my board was not completely clear of copper it made it more difficult. One recommendation is not to have the board like mine because at the moment of soldering you need too much precision, for us beginners it is not a good idea so as I didn't have the machine at home I had to do a copper clearance by hand on my second board.



Before soldering the ATtiny 85 I did the programming on my computer, this will be useful for when I connect my board with the USB input and I can recognize it. To do this I used FABINO, an arduino trainer that contains different components that helps me to make simulations and I used it in week 4 to start learning about electronics. Next I will show the steps for programming the ATtiny 85. ✔️



To get the programming I needed to download the ARDUINO 🙂 program from its official website (here) and download some folders to install the drivers (here). With this I followed a series of steps that I will explain below.



After getting the programming of ATtiny85 I had to solder it to my board, I was very careful with this soldering because the first time I did it I made a mistake in the orientation, I recommend to be very concentrated because otherwise there may be some details that not being fulfilled will spoil your whole process. 👌



The last step before connecting it to my computer is to do the current test, when this happened I realized that my board was short, I checked all possible connections and scraped them with my blade but it was still short. As a conclusion, after a long time, the problem was being my ATtiny, I tested it and it was burned. 😢 Here are the pictures.

Third attempt

On my third attempt I had to get another ATtiny for my plate, thanks to my partner Hayashi Mateo we were able to get the next day and continue with the next attempt. For this I had to remove once again the ATtiny and as I had put the soldering iron on it for a long time to change it, the copper started to come out. It was for this reason that I made use of my third plate, here I show some pictures.



After that I did the current test, all my components were correctly soldered (thanks to practice) and in particular it helped me a lot to use a socket because I think this protects a little more the ATtiny, for beginners like me I recommend to use it, just bend the legs at the base to solder it without problems. 💪



Apparently everything was going well, but my badge was not being recognized. This time I managed to see my LED light up and my computer beeped when I inserted the USB but it was telling me that the device was not recognized. What was going on? 😢



My first mistake was to solder this led resistor in another place, I had to correct it. After that I did the tests with the leds and the continuity between the traces. 🥵


Since there was a short between paths 1 and 4 and I still couldn't make the connection I made some new ways to solve my board. This board was much better soldered and I didn't want to mess it up so I fought to the end to make it work!

Finally

In order to finish with the functionality of my board I had to do three things, as there were still traces that shorted I had to use an external cable in the connection between pin 4 and trace 4 (because the current did not arrive), cut the track 4 to connect it with a copper wire (since a small part of the trace was not working either) and change the resistance of the green led because when I connected it to my computer it did not turn on (this resistance apparently had burned). Next I show part of the process.


The next step was to do the programming with the arduino program, this was the acid test so I was very scared because it would be practically my last attempt. 🐵

New design

In this new opportunity I made a circuit from scratch considering now new components, now I know that it is very important to be very cautious when building the board. One of the things I will not do again is to use the thick soldering iron, that does not help at all. Here are some pictures of the design process.



After choosing my components and distributing them on the plan as you could see, I chose to design an interesting shape this time, I have seen conventional plates and shapes of all kinds but I never saw one that reflected a symbol of any culture in Latin America. So I chose The chakana, this is a millenary aboriginal symbol of the indigenous peoples of the central Andes in the territories where both the Inca culture (southern Colombia, Ecuador, Peru, western Bolivia, Chile and Argentina) and some pre-Inca cultures (Peru and Bolivia) developed. Also called Andean Cross, it is a recurrent symbol in the original cultures of the Andes and its shape is that of a square and staggered cross, with twelve points. To start I used Inkscape and took the basic shape of this symbol, then I imported it into Easy EDA and used it to build the border of my plate. 🥰



Once the design was ready I made use of two more programs, FlatCAM and CNCjs, both help me to process the files generated from EasyEDA, below I share some images. The machine I use is called Roland Modela MDX - 20 and now that it is back in the lab I was able to test my board.



I really liked this work, designing something and then having it in your hands gave me a very nice feeling, everything we do these weeks are events that result from our own work and that's a very good thing. Here I share some final photos of the shape of my Electronic Chakana.

Electronic Chakana

Electronic Chakana

Update

Since my board did not present all the complete circuits because our MDX 20 modeling machine has a strange operation, when we send to cut, it reduces part of the board and eats some paths already milled, the solution I gave was to move my design in EasyEda and allow more space to my circuits.

Electronic Chakana