On Bluetooth Connected

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. Once paired, the other device may connect to the micro:bit and exchange data relating to many of the micro:bit’s features.

This block starts an event handler which in this case will run when something connects to your micro:bit using Bluetooth.

bluetooth.onBluetoothConnected(() => {});

Example

You could use this event handler to display a letter “C” on the micro:bit LED grid so you know you have a Bluetooth connection. Or you might want to send some data you’ve been accumulating to your smartphone as soon as it connects to your micro:bit. Maybe you’ve been using the accelerometer in your micro:bit to count your steps for example. Using this event handler you could send the accumulated step count to your phone when it establishes a Bluetooth connection.

bluetooth.onBluetoothConnected(() => {
    basic.showString("C");
});

Video - on Bluetooth connected

See also

About Bluetooth, micro:bit Bluetooth profile overview , micro:bit Bluetooth profile reference, Bluetooth on micro:bit resources, Bluetooth SIG

bluetooth