If you want to get started with motion sensors and the like, ESPHome makes it incredibly easy to build your own sensors.

The Luanode For ESP8266 and ESP32 is a WiFi enabled System On a Chip (SoC), provided by Espressif, for Internet of Things (IoT). its developer explains more about the inspiration design and ...

Since the ESP8266 came on the scene a few years ago and revolutionized the way microcontrollers communicate with other devices, incremental progress on this chip has occurred at a relatively even ...

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.