7. Electronics design¶
KiCAD¶
Using my design in Wokwi from the Embedded programing week, I designed a PCB for an ESPC3 using the button code.
I first had to downlaod the Fab Academy library for KiCad, to make sure I had the right parts.
Then it was off to making my schematic. I used my Wokwi and coppied what I had on there, the only difference was that I used the footprints of SMD components instead of through hole ones.
After I had my Schematic I then imported it over to the PCB design page. I placed my components as compact as I could while staying aware of limitations such as the USB-C port at the top of the C3. I also made all of my tracks .5mm instead of KiCads default fo .2mm, which does not stay on the board.
Once I had the PCB layout complete, I could then view the 3d model in KiCad’s PCB viewer.
Milling¶
We used Bantam Tools’s desktop milling machines to create our PCBs.
I had some clearance issues with the board, this was an incredibly easy fix though as I milled anyway, and then went back with tweezers and cut those bridges manually. I double checked with a multimeter to make sure they were truly disconnected.
(The red marks are places where the 1/64” flat endmill bit can’t reach)
One of our milling machines has a problem with sensing duuring touch off. Since we can no longer order the part, as the manufacture has discontinued this model, we are now using an alligator wire connected to the drill bit and the head of the machine, while janky, it does work well enough until we order new milling machines next year.
Video of milling the board:
After milling, this is what my board looked like:
Soldering¶
Soldering went super smothly except for one small detail, my LED was on backwards. When I tried to take off my LED, I ripped the trace. I fixed this easily by subsituting the trance with a 0ohm resistor.
My first attempt at soldering (LED was backwards):
My second attempt at soldering my PCB (trace ripped and I bridged it with a 0 ohm resistor):
Coding¶
I just used some old button code from my Embedded Programming week. I programmed the chip through Arduino since I can’t be bothered to use Thonny.
const int buttonPin = D1; // the number of the pushbutton pin
const int ledPin = D0
; // the number of the LED pin
int buttonState = 0; // variable for reading the pushbutton status
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}
void loop() {
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed. If it is, the buttonState is HIGH:
if (buttonState == HIGH) {
// turn LED off:
digitalWrite(ledPin, HIGH);
} else {
// turn LED on:
digitalWrite(ledPin, LOW);
}
}
This is what the final board looks lke running:
Reflection¶
This week was a slight learning curve for me because I had partially forgotten how to use KiCad. Thankfully, I was able to quickly use trial and error to produce my PCB board quickly. Everything (Besides the soldering) was pretty chill this week, I didn’t find myself rushing too much to get everything done. I also think that looking at the signals from the oscilloscope was really interesting.
Useful links¶
SoftWare Used¶
My Group’s Site¶
| Members | Role |
|---|---|
| Andrew and Kathryn | Documentation |
| Kathryn | Sigilent Oscilloscope |
| Kathryn | Multimeter |
| Andrew | Analog Discovery 2 (Logic Analyzer) |