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Activity

Scratch guitar

Beginner | Scratch | Buttons, Pins | Harmony, Input/output

Step 1: Make it

What is it?

Play real chords on an electric micro:bit guitar.

photo showing tin foil pads wired up to micro:bit pin 0, 1, 2 and GND on a cardboard guitar

How it works

  • Make a guitar or keyboard from cardboard and foil like the one in the picture.
  • Connect tin foil pads to the 0, 1, 2 and GND input pins on the micro:bit.
  • When you touch the GND pin and one of the other pins, the program plays the note F, A or C in a guitar sound on your computer’s audio output.
  • If you press them all together it plays the 3 notes at the same time. This is an F major chord.
  • Pressing button A or B on the micro:bit causes the program to shift the pitch up or down an octave (a pitch shift of +120 or -120 is up or down one whole octave – 8 notes).
Screenshot of Scratch project

What you need

  • micro:bit and optional battery pack
  • suitable computer with Scratch link installed. See https://scratch.mit.edu/microbit for details on how to get Scratch working with micro:bit
  • 4 crocodile clip leads
  • cardboard, scissors, glue, tin foil

Step 2: Code it

Scratch code blocks for the guitar sprite

Code blocks for the guitar sprite

Step 3: Improve it

  • Make the pitch change more subtle with smaller numbers: try 12 instead of 120.
  • Add a volume control by measuring the angle of tilt of your micro:bit guitar.
  • Add more chords or change the instrument sound in Scratch.