A Lua based Digital Signage tool (written in C/Lua) for the Raspberry Pi. And a complete SaaS platform (mostly written in Python) around that tool, so you don't have to understand neither of them and can get everything up and running in 5 minutes. It's commercially used and growing. And a lot of fun. https://info-beamer.com/pi (the tool/standalone program) and https://info-beamer.com/hosted (the SaaS). Feedback welcome!
