Chapter 9. Pen Plotter

In Chapter 8, we made our robot using continuous rotation servo motors, but the most common type of servo motor can only rotate by around 270 degrees. While these motors can’t be used for robot wheels, their ability to repeatedly move to an absolute position makes them useful for all kinds of other things. Here we’re going to use them to control the position of a pencil so that we can draw shapes.

Experiment 14: Pen Plotter

You’ll need:

  • A small corkboard (roughly 30cm x 40cm)

  • 3x 9g RC servo motors (not continuous rotation) with their servo plates

  • One servo motor extension wire

  • 9x patch leads

  • Breadboard

  • Espruino Pico

  • A 47uF, 6v (or higher) capacitor (optional)

  • An old pencil with soft lead (2B or softer ...

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