I’ve built my own intercom system (speaker & mic), door bell, electric door opening, and camera system with an iOS companion app and integrated all of it in my old door bell system.

Technically, I built my own “Ring” system without Cloud reliance using ESP-IDF SDK, a few MCU boards (XIAO ESP32-S3s and one C6), some capacitors and resistors, and push buttons + Tailscale setup. (Total project length: 3-4 months)

Out of boredom I also built a Bluetooth Mic Bug with a 200mah battery with a Nordic Semiconductor MCU (nRF54).

That being said, my own “Ring” system is the stuff I’d say is really useful to me, while I’d consider the Bluetooth Bug as an experiment, because I just wanted to test nRF Connect SDK.

I’d like to build more useful things, what would you build? I’m open to anything useful, bonus if it’s totally insane