Having the ability to send secret messages is a critical spy skill. By harnessing the power of radio waves and using Morse code, you can transmit your plans to your base station for your fellow operatives!

The Gemma M0 can act as a basic AM radio transmitter by taking advantage of M0 chip's digital-to-analog converter (DAC) and direct memory access (DMA). Here's more info on how this clever hack by our own Phillip Burgess works.

You’ll tell other operatives nearby to tune in to your chosen frequency, and then you’ll send your Morse messages with a specially built Morse code keyer attached to the Gemma M0.


1 x Gemma M0
Wearable microcontroller board
1 x Woven Conductive Fabric
For building contact switches
1 x 3x AAA Battery Holder
with On/Off Switch and 2-pin JST
1 x USB Cable
A/MicroB - 6"


In addition to the above parts, you'll also need:

  • An AM radio to tune in the Morse transmissions
  • Wooden clothespin
  • Small block of wood, approximately 2-1/2" x 5" x 3/4" (a.k.a. a 5" length of nominal 1" x 3" lumber)
  • Two nails that fit in the clothespin spring coil and are electrically conductive
  • Double stick tape
  • Two small rubber bands
  • Stranded wire or alligator clip leads

This guide was first published on Mar 08, 2018. It was last updated on Jun 11, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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