In order to use the ESP-01 Wi-Fi relay module, a programmer/programming adapter is required to program the ESP-01 module (see below). Also it is pretty easy to make your own programmer, or you can ...

Simply, it’s an Arduino library for communicating with Modbus slaves over RS232/485 via RTU (remote terminal unit) protocol. In conclusion, the Modbus 2-channel 5V relay module is a very useful device ...

Components Needed: Raspberry Pi 4. Arduino Uno. 4-channel relay module. PIR motion sensor. Steps: Use Arduino to handle sensor input and relay control. Pi runs a Python Flask server with a simple UI ...