Lesson 4: Radio Messaging

In this lesson, you’ll learn how to use the Radio feature on the Micro:bit to send and receive messages wirelessly between two or more Micro:bits. By the end, you’ll make a simple wireless chat system that sends numbers or short messages from one Micro:bit to another.

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What You’ll Learn

• What the radio is and how it works.
• How to set a radio group so Micro:bits can talk to each other.
• How to send messages or numbers wirelessly.
• How to receive and display messages.

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Steps

1. Open MakeCode Tutorial

Happy to work through this on your own? Go to: https://makecode.microbit.org/

If you need some extra help click here instead

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2. Set the Radio Group

Just like walkie-talkies, Micro:bits must be on the same channel to communicate.

• Go to Radio.
• Drag radio set group 1 into on start.

In a classroom, each pair of students should choose a different group number so projects don’t overlap.

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3. Send a Message (Button A)

• Go to Input → drag on button A pressed.
• Go to Radio → drag radio send number 1.

Test it:

• Press A → the Micro:bit sends “1” wirelessly.

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4. Receive Messages

Now make the Micro:bit show something when it receives a radio message.

• Go to Radio.
• Drag on radio received number.
• Inside it, add show number (from Basic).
• Set it to show the received number.

Test with two Micro:bits:

• Press A on one → the other shows 1.

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5. Send a Different Message (Button B)

Let’s add a second button:

• Go to Input → on button B pressed.
• Add radio send number 2.

Now:

• Press A → sends 1
• Press B → sends 2

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6. Extra Challenges (Optional)

Check out more radio games Try one or more:

• Send a word instead of a number
  • Use radio send string.
• Create a counting system:
  • A = +1
  • B = –1
• Add sounds when a message is received.
• Create a simple filter:
  • Only show the number if it matches a password.
• Combine with variables for a multiplayer scoreboard.

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Reflection

• Why is radio communication useful?
• Where might wireless messaging be used in real life?
• How could you combine variables + radio to make a multiplayer game?