Lightning-network uses hot wallets, real-world payments are made from phones. The burden of connectivity can be taken away from the point-of-sale and given to the phone.
For a traditional PoS experience see my LNPoS project.
LNURLPoS uses the LNURL-pay protocol. LNURL-pay allows your lightning-wallet to make a secure request to a server to get a lightning-network invoice. So instead of scanning a massive ugly lightning-network invoice QR, you can scan a lovely little LNURL QR (if you decode an LNURL you'll see its just a URL).
For online stuff I suppose massive QR codes are not an issue, but when fiddling with hardware devices they are. LNURLPoS using the LNURL-pay protocol, it can use a smaller screen for displaying the QR.
- LNURLPoS server set up and register PoS in a few clicks on LNbits using the LNURLPoS extension
- Copy credentials (including a secret key) from server to the physical LNURLPoS device
- Merchant enters amount into LNURLPoS device
- LNURL is generated in device and displayed for scanning (LNURL includes a unique pin encrypted using the secret key shared with the server)
- Customer scans and pays
- When the payment has cleared the customer is sent the decrypted unique pin
- Merchant can compare and verify using the same pin displayed on the lNURLPoS
Stepan Snigerev for creating beautiful crypto and LNURL encoding functions.
Fiatjafs incredible OfflineShop extension. LNURLPoS is the same concept, but can run at scale, and is dependent on a device.
- Lilygo TTGO T-Display
- Keypad membrane (these big ones are easy to find, these smaller ones will be used for workshops by arcbtc).
- Download/install latest Arduino IDE
- Install ESP32 boards, using boards manager
- Copy these libraries into your Arduino IDE library folder
- Plug in T-Display, from Tools>Board>ESP32 Boards select TTGO LoRa32 OLED V1
To make things easy (usually a few clicks on things like Raspiblitz), there is an LNbits extension. If you want to make your own stand-alone server software that would be fairly easy to do, by replicating the lnurl.py file in the extennsion.
Recycle the T-Display case, as with the smaller keypad it all fits together perfectly. See demo
Alternatively, there are 2 lightburn designs for cases depending on membrane keypads. Designs use layered 3mm acrylic and M4 nuts/bolts
(Blue = fill/engrave 1.5mm depth, Black = cut)
Laser cutters are cheap now and should be part of every makers arsenal, these examples were cut on £200 NEJE Master2s 20W, alternatively there are plenty of laser engraving/cutting companies.