Radio Not Working

How to Fix It

1. Check the radio group number on both Micro:bits.

   Both Micro:bits must have the same group number in their radio settings. In MakeCode, look for 'radio set group' block — ensure both programs use identical numbers (e.g., both set to group 1). In MicroPython: radio.config(group=1) — must match on both devices.

2. Confirm radio.on() is called before any send/receive.

   The Micro:bit radio must be explicitly turned on in code. In MakeCode, use the 'radio on' block at the start of the 'on start' section. In MicroPython, call radio.on() before any radio.send() or radio.receive() calls.

3. Reduce distance and remove obstructions.

   Micro:bit radio range is approximately 70m in open air, but concrete walls reduce this to 10–15m. Bring the two Micro:bits within 1 meter of each other to test first. If they communicate at close range, the issue was distance or interference.

4. Re-flash the program to both Micro:bits.

   Copy the program .hex file to both Micro:bits (or re-flash from MakeCode/Mu editor). A fresh flash ensures both devices are running the same version of the code with no corrupted state.

5. Test with the MakeCode radio example.

   Load the built-in 'Simple Radio Send' example from MakeCode's project gallery onto both Micro:bits. If the example works, the issue is in your own code. If the example also fails, the radio hardware may be at fault.