Flute Systems has built an Arduino based remote buzzer system. The larger display can be a PC connected camera focused on the base station, then to a projector. Or using a phone camera to PC/other device via the Internet.
We are making available (open sourcing) most of the build data such that anyone needing such a system can make it or get it made. And get existing systems repaired / modified easily. Scroll down for the code, circuit diagrams, Fusion 360 files, STL files, Cura profiles (settings) and G-Codes for 3D printing the enclosures. Any questions, additions, modifications, suggestions and advice are welcome. Features yet to be implemented are custom PCBs using individual components, a four position switch to set the buzzer unit’s number, battery indicator light, charging ports, and a carrying case.
The design uses Adafruit PowerBoost 1000C boards