Week 5: Making and Testing a Microcontroller Development Board

Overview

This week, I worked on making and testing a microcontroller development board based on the design I developed during Week 4. After finalizing my PCB design using Fusion360 and exporting it, I proceeded to mill and assemble the board to bring it to life. My goal was to ensure that all components were properly soldered and that the board would respond to initial power-on tests.

Process & Testing

I started by milling the board based on my design. The PCB milling process involved using a precise milling machine to carve out the circuit traces on the copper plate. Below are some images documenting the process of milling and testing the board.

PCB Design on Screen Milled PCB Board

Once the milling was complete, I verified the traces to ensure there were no shorts or missed connections. I then soldered the components onto the board, carefully adding resistors, capacitors, and the microcontroller chip.

PCB Milling Process Soldering Components onto the PCB

After soldering, I connected the board to power and ran basic tests to ensure it functioned as expected. The initial power test confirmed that the microcontroller powered on correctly, and I started running basic input/output tests to verify the connections.

Part 2: Debugging & Iteration

Although the button and LED worked as expected, the analog microphone wasn't functioning correctly. To diagnose the issue, I used both a voltmeter and an oscilloscope to track signals and check for problems in the circuit.

Debugging with Voltmeter Oscilloscope in Debugging Process

After some troubleshooting, I realized that I had forgotten to include a capacitor in the original design. This small oversight was causing the microphone to malfunction. I milled a new PCB with the missing capacitor and started fresh. Below is an image of the corrected board:

Forgot Capacitor on PCB Newly Milled PCB with Capacitor Added

Debugging this board has taught me valuable lessons about iteration and attention to detail. It's easy to overlook small components like capacitors, but they can significantly affect the functionality of the circuit. During the process, I couldn't help but wish I had friends in Shenzhen who could print these boards for me faster! A huge thanks to Yuval for guiding me through the debugging process.

The project is still a work in progress, but I hope to have the microphone configured soon so I can integrate it into my final project. I'm excited to continue working on this and see it come together as part of my AR wearable glasses.

PCB Tests

Here are some videos showing the button and LED tests on the working PCB:

Reflection

This week’s project was a great hands-on experience, as it was the first time I milled and assembled a custom PCB board. While soldering required a steady hand, I learned a lot about how to ensure clean connections and avoid solder bridges. The process of debugging the board also gave me insights into checking connections and verifying circuits step by step.

I am also considering adding another manufacturing method for extra credit, such as 3D printing the board housing to give the circuit a sleek, compact look. Shout out to my TAs, Sam Bruce and Anthony Penne, for their guidance during the milling and soldering process. Their insights made all the difference!