Physical front-end for the Lightning Network ⚡️
Sploony is firmware that lets ESP32 SoC boards interact with the Lightning Network. One or multiple Sploonies can connect directly to a single lnd to display machine-readable invoices, and act upon its invoice once paid. See a video of it here: https://twitter.com/sakak_musdom/status/1084857547947880448
The ESP32 platform is the cheapest hardware capable of practical secure connection to lnd, many of which form the cheapest practical payments network. A board from Aliexpress costs US$7 plus shipping. This combo enables many new business use-cases: micro-Point of Sales, sub-cent vending machines, public lockboxes, charging stations etc.
If you have an lnd node with a publicly reachable REST gateway, and an ESP32 development board, you can compile and run Sploony using PlatformIO or Arduino IDE. A quick guide can be found here.