For another device like a smartphone to use any of the Bluetooth "services" which the micro:bit has, it must first be [paired with the micro:bit](/reference/bluetooth/bluetooth-pairing). Once paired, the other device may connect to the micro:bit and exchange data relating to many of the micro:bit's features.
The Bluetooth button service makes it possible for another device such as a smartphone to be notified wirelessly whenever a button on the front of a micro:bit is pressed. Each of the two micro:bit buttons can be in one of three possible states:
* Not pressed
* Pressed
* Long press - pressed and held down for at least 2 seconds
The button service allows you to make other things which are connected to your micro:bit using Bluetooth respond in some way when you press either of the buttons. You could, for example, hide your smartphone somewhere in the room and have it make an amusing noise when you press either of the buttons on your micro:bit. We'll leave it to you to decide what would be amusing.
No additional code is needed on the micro:bit to use the Bluetooth button service from another device.
For more advanced information on the micro:bit Bluetooth button service including information on using a smartphone, see the [Lancaster University micro:bit runtime technical documentation](http://lancaster-university.github.io/microbit-docs/ble/button-service/)
