// the find
arcbtc/M5StackSats
A bitcoin point of sale terminal using the ESP32 based M5Stack
A DIY Bitcoin Lightning Network point-of-sale terminal for the M5Stack Faces kit — an ESP32 device with a built-in keypad and display. You flash it, connect it to LNbits or BTCPay Server, and you have a $55 hardware POS terminal. The author has since superseded it with LNPOS, which the README itself recommends over this.
Multiple backend variants included (LNbits, BTCPay Server, LND, LNPay) so you can pick your Lightning node setup. The hardware choice is good — M5Stack Faces has a real keypad and charging dock, not a breadboard hack. C/Arduino codebase is readable and small enough to understand fully before flashing to hardware.
Abandoned in 2021 and the README explicitly redirects you to a different repo — there is no reason to use this over LNPOS. No error handling visible for failed HTTP requests or invoice polling timeouts, which will silently hang on flaky WiFi. Hardcoded credentials/config scattered in header files rather than any kind of config provisioning, so every flash requires code edits. No certificate validation on HTTPS calls to your node, which matters when your node holds real money.