Another one of those pointless projects but do you know what … I'm a sucker for anything with a LED.
This time it involves a 'PixMob IR LED Wristband' which I manage to procure recently at Coldplay gig up in Manchester (UK).
These are handed out to attendees and activated via either infrared or radio frequency during the certain parts of the concert.
To use it outside of its intended area (at home) requires an Arduino/ESP32, IR Transmitter and some Python magic. You'll find all the details and guide here.