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Aijia Yao

MIT EECS • HTMAA 2025

Week 6 – Electronics Production

October 2025

This week was mainly about PCB production.

What I Did

PCB Design

    Before milling the PCB, I reviewed my design from last week of a simple PCB with XIAO-RP2040 microcontroller and RGB LEDs.

    Component Specification
    Microcontroller XIAO-ESP32-S3(simulation);XIAO-RP2040(real design)
    LED NeoPixel Compatible LED (WS2812B, see datasheet)
    Button Tactile switch (TS04-66-43-BK-260-SMT, see datasheet)
    Although the footprint of each RGB LED is the same, there are two different configurations of RGB LED as shown below:
    pcb
    Two different RGB LED configurations.
    To make the wiring easier, I chose the one on the right, which is compatibale with NeoPixel library.

PCB Milling

Then I milled the PCB using Bantam Othermill. The process is quite straightforward.

  • First, I secured the copper board on the milling bed with double-sided tape.
  • Next, I loaded the .gbr file into the software and set the origin point.
  • After that, I just needed to press "Start" and change the milling tool if necessary, then just wait for it to finish.
  • (The whole process took around 10 minutes)
pcb
From left to right, the pcb layout, trace pattern and the milled pcb after soldering&debugging.
From the picture above, we can see that the milling is quite precise and clean. After milling, I soldered the components onto the PCB. The final product is shown in the figure on the right.You can see that I use a jump wire to connect the first LED to 5V pin of the microcontroller, and the rest of the LEDs are connected in series. Based on this design, I can control the color and brightness of each LED individually using the NeoPixel library in Arduino.

Other Notes

  • The gerber files for copper layer is here and the edge cuts is here.
  • After debugging with a multimeter, I confirmed that all connections were correct and the circuit was functioning as intended. The full play around with this PCB is discussed in Output Device Week.