Arcbtc made interesting completely offline Bitcoin Lightning Network point of sale device for around $10 using simple TTGO T-display device with keypad membrane.
LNURLPoS uses the LNURL-pay protocol that allows lightning wallet to make a secure request to a server to get a lightning-network invoice, with bech32 encoded URL string.
Interesting thing that I like about this project is that it doesn't need internet connection and if you add battery you don't even need to have direct power connection.
Hardware needed:- ESP32 TTGO T-Display (around $10)
- Keypad membrane (around 1$)
- Angled male/male GPIO pins (around $7)
- 3d printed case
Arduino software install:- Download/install latest Arduino IDE
- Install ESP32 boards
- Copy libraries into Arduino IDE library folder
- Plug in T-Display, from Tools>Board>ESP32 Boards select TTGO LoRa32 OLED V1
Source:
https://github.com/arcbtc/LNURLPoSVideo Tutorial:
https://youtu.be/ofCv2cHZ5b0Watching this tutorial you can find one more interesting open source project called Bleskomat that is using same LNURL-pay protocol for next generation offline Bitcoin Lightning ATM device, that is using shared secret to encrypt data.