In essence, you connect a common 433 MHz receiver module to an ESP32 or ESP8266 microcontroller, and have it wait until a specific device squawks out. From there, the code on the ESP can fire off ...

We can say one thing for [bitluni]: the BOMs for his projects, like this ESP32 AM radio transmitter, are always on the low side. That’s because he leverages software to do jobs traditionally ...