on Received Buffer

Run part of a program when the micro:bit receives a buffer over radio.

radio.onReceivedBuffer(function (receivedBuffer) {})

The data contained in receivedBuffer is put there as a data type. The data might be a number or a string. When using buffers though, the way the data is placed in the buffer must have a specific format. In particular, numbers must have a certain order when their individual bytes are placed into the buffer. The numbers must also be retrieved from the buffer using the order that they were placed in when set there. You can read more about number formats.


  • receivedBuffer: The buffer that was sent in this packet or the empty string if this packet did not contain a string. See send buffer

Example: Remote level

Two micro:bits work like remote levels. They lie flat and detect any change in the horizontal position of the plane that they sit in. Each board sends its level measurements to the other. Each level measurement is shown on the screen.

let ax = 0;
let ay = 0;
basic.forever(() => {
    ax = input.acceleration(Dimension.X);
    ay = input.acceleration(Dimension.Y);

    // encode data in buffer
    let buf = pins.createBuffer(4)
    buf.setNumber(NumberFormat.Int16LE, 0, ax)
    buf.setNumber(NumberFormat.Int16LE, 2, ay)

radio.onReceivedBuffer(function (receivedBuffer) {
    // decode data from buffer
    ax = receivedBuffer.getNumber(NumberFormat.Int16LE, 0);
    ay = receivedBuffer.getNumber(NumberFormat.Int16LE, 2);

    // display
        pins.map(ax, -1023, 1023, 0, 4),
        pins.map(ay, -1023, 1023, 0, 4)

A radio that can both transmit and receive is called a transceiver.

See also

send buffer, number formats