These days, 433-MHz RF transmitter/receiver modules are very popular with electronics hobbyists and tinkerers. These cheap short-range radio modules can be used with almost all microcontrollers for a ...

This is an example code written to showcase the usage of RF Module and WiFi to control a relay to lock and unlock a door. The ESP32 Dev Board is connected to a 433MHz RF Reciever and a Relay. You can ...