A standard Bluetooth module has to have HID firmware installed. [Dastardly] makes a homemade daughterboard–er, shield–to connect it to the Arduino. The result is a nice little sandwich with a ...

His build uses an Arduino Mega with a BlueSMiRF Silver Bluetooth ... and initiates a connection if in range. Doors are unlocked directly through a 2-channel relay module, and an LED indicator ...