In the summer of 2018 I worked on converting a vending machine in MIT’s Media Lab that was previously hacked to accept (on-chain) Bitcoin payments, to accept payments over the Lightning Network. The end goal was to demonstrate this at the Media Lab’s Member Week event in October 2018. The demo needed to be multi-currency to also demonstrate the ability to perform off-chain atomic swaps.
We retrofitted the vending machine with a Raspberry Pi, running lit - a multi-currency Lightning Network client. We ran three distinct testnet chains (Bitcoin, Litecoin and a fake US-Dollar chain). Users could send the vending machine any currency, which it would convert to USD equivalent value and credit it on the vending machine, after which users could make a purchase.
The demo was completed by adding a cross-platform mobile wallet app (Android and iOS) that the users could install, and use to interact with the vending machine.
I contributed to building the mobile app(s), remote control ability of the lightning nodes, implement HTLC (Hash-Timelock Contracts) in lit, and setting up the entire demo environment.