Driving tricolor E-Paper price tags with an Arduino

ePaper price tags are becoming popular items in the hacker community as a cheap way to tinker with technology. [Aaron Christophel] got his hands on a 4.4″ model with red, black, and white colors, and proceeded to program an ESP32 to raise the price instead.

The protocol used by the display was reverse engineered by having the display update itself via RF and monitoring the signals sent between the microcontrollers on the display's control board. Once the protocol was understood, one of the microcontrollers could then be removed and replaced with an ESP32 for direct control. Implementing this requires some disassembly and tricky soldering, but nothing should scare off an experienced hacker.

With the correct code flashed on the ESP32, as available on Github, it is possible to run the display directly. The hacked code does an excellent job of driving the display, showing crisp lines and crisp colors that indicate the e-Paper display is working properly.

We've seen [Aaron]'s work in this area before, when he hacked into simpler two-color e-ink price tags. He also went so far as to create entire wall displays out of salvaged displays, which is quite impressive. Video after the break.