Week 06

This is my 6th week at FabAcademy. This week’s assignment entails the following tasks:

group assignment: use the test equipment in your lab to observe the operation of a microcontroller circuit board individual assignment: use an EDA tool to design a development board that uses parts from the inventory to interact and communicate with an embedded microcontroller extra credit: try another design workflow extra credit: simulate your design extra credit: design a case around your design

Group Assignment: surveying the operation of a circuit board with an oscilloscope

In the first part of this week’s assignment we learnt the basic functions of an oscilloscope to understand the potentiallity of this device towards circuit surveying. An oscilloscope is an apparatus capable of measuring any voltage signal variation, which delivers a lot of possibilities for understaing the operation of circuits. In particular, we used the arduino one microcontroller board to check out signal variations of the different components. Here you can see an image of our on-hands working with the oscilloscope:

See a detailed explanation of our exploration with the oscilloscope in the following link: https://fabacademy.org/2025/labs/aindustriosa/week06.html

Individual assignment: designing a PCB with KiCad 8.0

Regarding the individual assignment, I used the software KiCad v8.0 for designing a PCB that uses the microcontroller XIAO ESP32C3 and interacts with several devices of our inventory. To start with this task, I first downloaded the KicadFab Cloud from git, which comprises a library containing most of the devices to be used in our FabAcademy. Then I uncompressed the library in the KiCad folder:

After downloading the Fabcloud library, I installed the library by just setting the corresponding path in the library and footprint preferences, which allows KiCad to fully utilize all the downloaded tools.

Then I added the microcontroller which I would use for playing with the different devices, in my case the Xiao ESP32c3. This microcontroller was previously reviewed and you can find a complete description of its characteristics here: https://fabacademy.org/2025/labs/aindustriosa/week04.html

Once included, I started the interaction playing by including a LED, in my case I used the Led1206, which also needs a resistance for properly working. Based on other designs presented by Neil, I included the 1k resistance 1206 as well:

Then I included the proper flags for connecting the led and resistance to the microcontroller. According to the specifications of Seedstudio, led can be connected to a digital pin, in my case I selected the pin number 10, which was defined also besides the led and resistance in series. On the other side, the power ground flag was also defined, which was includded also along with a power flag in the 13th pin of the Xiao. Also I closed all other pins to prevent error while conducting the electric rules checking. Here you can see an schematic of the circuit designed.

After completing the main schematic of the circuit, I defined a new width of track and net classes to be, respectively 1 mm and 0,4 mm thick. This selection will prevent fabrication errors and problems related with cooper bridging.

Next, I switched from schematic to PCB editor and started the possitioning and wiring of the different devices to make it as simple and clean as possible:

The resulting circuit design was then exported as svg and visualized in Inkscape as shown below. Although the circuit can be further cleanesed (see details in the upcoming steps), still the presented design could already be sent for PCB production.

Once that simple design was exported, I continued playing around connecting other devices from our inventory, and I selected a three-way horizontal connector from the fab library, specifically I choosed the PinHeader 01x03 P2.54mm Horizontal SMD:

This three way connector can be useful for connecting a range of sensors. In my case I was interested in tempereature sensor, as it will be necessary for my final project. The three connectors need to be connected, respectively to data digital pin, power and ground, thus I included the corresponding labelling and connected the data to the first microcontroller pin. In addition, I also included a 4-pin connector which can be used for a wide range of devices, as for instance an OLED for monitoring temprature sensor reads, or for instance a servocontroller (which also will be necessary for my final project). After physical inspection of the 4 pin of our inventory, I realized that first and second pins need to connect to SDA and SCL ports, while 3rd and 4th to to power and ground. This was therefore labelled in the schematic as well as connecting the SDA and SCL ports in the 5th and 6th connectors. The design resulted thus in the following:

Then I switched to PCB editor but I realized that there will be some troubles with the wirking of the SDA port, therefore I used the trick of the 0 Ohm resistance to use the resistance as a bridge for wiring:

By setting the power wiring with 1mm and 0,4 mm in the rest parts, as well as defining a rectangle of board edges and 3,2 mm circles for potential screwing, the PCB design of mu board resulted in the following

For avoiding problems with wiring of the ground (necessary for all devices), I included a copper zone properties as filler, which allows for all grounds to be automatically connected with the microprocessor ground:

This resulted in the following PCB design including the filler

Once the PCB was detailed, I, again, expeorted it to svg. But this time I downloaded and used GIMP for opening and manipulation. Originally, the board looked like this in GIMP after defining a resolution of 1000 pix:

I removed internal parts of the microcontroller - connections that I will not use, as well as marked dots that are unnecessary and just would make the fabrication process longer and more expensive. Finally, after manipulation, my PCB looked like this:

Files for download and replication

Here you can download all the files of the first project with KiCadRar

Here you can download all the files of the second project KiCadRar2 and Gimp final design GimpDesign.