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 ...

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 ...

Using an HC-05 Bluetooth module, it’s possible to get this iPod-connected Arduino to relay data to and from an Android device with a small app.

The Arduino pulls song information to be displayed on the graphic LCD screen, and sends commands to the iPod when it detects a button push. See a quick demo of the setup after the break.