“A clock that displays using randomly selected MNIST digits.
Hardware/software implementation by Dheera Venkatraman
It uses an TinyPICO which is an awesome, compact ESP32 board with plenty of GPIO pins, 4MB flash, Wi-Fi, and lots of other features not needed for this project.
4 e-Ink displays are used for the digits. I chose e-Ink since it matches with the idea of handwritten digits, works well in all lighting conditions, and doesn’t light up your bedroom when you’re trying to sleep. The Waveshare e-Ink displays are mostly SPI, although they have some annoying extra pins. One would wish they were just SPI + one CS pin for each board, but a few more connections are necessary. Here is a diagram of the connections to the ESP32. Crimp the wires according to this.”