Looking for practical Arduino projects? This guide shows how to control a relay from your smartphone using an Arduino Uno — ...

An Arduino mini pro provides the brains. A FT-232 USB to serial board is used to program the Arduino. A standard Bluetooth module has to have HID firmware installed.

The project is build around an Arduino ProMini, an FTDI breakout board, and a Bluetooth module. It’s a fairly simple build, but the meat of the project lies in the code.