Ideas & Design

I'd like to use pairs of phototransistor and LED to test something and measure the rate of oscillation.

circuit's schematic design PCB design

PCB Milling

startmilling milled PCB board

The CNC process went well! Thank you Lindong for you G-Code!

Also thank you to my best friend Quincy for providing CNC machine!

Soldering

Flux is your friend! Start soldering

BUG1

Unfortunately, I forgot to drill holes on the pins during the CNC machine so I decided to drill them manually.

Lindong found out a way to manually control CNC and mill it on the PCB board. Then I did it by myself.

It turned out to work very well!

BUG2

Since my two PCB will be placed in a "face-to-face" way, I should have mirrored one of them, but I forgot to do so...

To debug, I cut off some part of my PCB. I soldered two jumping wires to swap two pins, one of which connected to GND.

Final Prodcut

The final product looks clean and satisfying.

I also designed a shell for my device and 3D-printed it.

Input test

My first test proved that the phototransistors on the device is able to capture the change of the pattern of the LEDs on the other side.
The other test showed that the device is able to sense the rate of the osscillation inside, which moves like a pendulum.