On another of this half sleep ideas one night I was playing with one of this 2.7" small epapers with touch interface and I though, why not to make a simple digital switch?

It's made by 2 PCBs. One provides 3.3DC converted from Mains power and receives 2 signals (50 ms HIGH) that move a latch relay TICK, TICK and switches on /off something.

Second one is the epaper w/touch controller. The MCU we choosed to drive it is ESP32-C3 (About 2.60 USD)

On the back of that PCB is the epaper itself, where we drawn with C++ and the second tick of an RTC, the basic interface you can see here:

https://github.com/martinberlin/bistable-smart-switch/wiki

For more information please visit the WiKi. We will add some units to our Lectronz store soon (At the moment is out-of-stock)