Graduation Cap
May 2019
RGB LED Matrix mounted on a university graduation cap to show a simulation of Conway’s Game of Life.
My initial idea to cover the entire area was to use alternating strips of addressable LEDs but then I came across these individually addressable 8x8 matrixes. It also worked out that 3 of them side by side would perfectly cover the width of my graduation cap.
Conway’s Game of Life Simulation
The Cap ran a real time simulation of Conway’s Game of Life then processes the grid to be sent to the addressable LEDs. When the number of live cells drops below 10%, the simulation is reset.
Electronics
| Part | Unit Price | Quantity | Total | |||
|---|---|---|---|---|---|---|
| RPi Zero W | $22 | 1 | $22 | |||
| WS2812B 8x8 RGB Matrix | $19 | 9 | $171 | |||
| 2S LiPo Battery | $20 | 1 | $20 | |||
| Other Parts | Buck Converter, Switches, Connectors, Protoboard, Project Box, 3 Conductor Cable | |||||
| Project Total | ~$230 | |||||
The cap got featured in a CSUF Facebook post of creative graduation cap decorations.
Notes / Improvements
Enclosure Cooling
While sitting at my graduation ceremony the project box containing the Raspberry Pi and buck converter got warm and the buck converter itself was hot to the touch. Some form of active or passive cooling would be beneficial in a future design.
Isolate Power
When connecting / disconnecting the tether or turning the power to the matrix on and off, the 5v from the buck converter would sag causing the Raspberry Pi to hard reset. Isolation of the Raspberry Pi from the matrix is recommended.
Communication & Content
Since this project was time limited (I thought of it 2 weeks before graduation, on top of finals and capstone) I was unable to add additional content like scrolling text or more animations. I also wanted the ability to connect to the cap from my phone to change the animation or text being displayed.