You can already work with micro:bit inputs and the display. Today you will connect two micro:bits with radio so one can send a message and the other can show it.

This is the next part of your coding project. Open the project you saved earlier and keep building at your device: predict first, then build, run and fix.

Two micro:bits can only hear each other if they are on the same radio group. A radio group is just a number, and it works like a channel: set both to 1 and they talk; leave one on a different number and nothing arrives, with no error to tell you why.

That is the first thing to get right and the first thing to check when a message does not turn up. Today one micro:bit sends and the other shows what it receives: first a message, then a number, then a name and a value together.

Go to the https://makecode.microbit.org website and create a new project.

The first thing we need to do is set the radio group that our Micorbits will be broadcasting on. A radio group is the channel that the Microbit both sends it's messages and listens for other messages. A Microbit can only send or receive in one group at a time.

A Microbit that is on radio group 2 will not be able to receive a message from another Microbit that is on radio group 3. However if they are both on radio group 3 then then we can communicate with each other.

Add the following code to set the radio group to 1.

radio.setGroup(1)

We can send different types of messages, we can send:

1. A string (text) message.
2. A number message.
3. A name and value message.

Let's start off my sending a string message. Add the following code to send the message "Hello" when you press the A button.

input.onButtonPressed(Button.A, function () {
    radio.sendString("Hello")
})