Servo for micro:bit

by Monk Makes

The MonkMakes Servo for micro:bit board provides a really easy way to attach up to three servomotors to a BBC micro:bit. The board requires a power supply or battery pack to provide 5 or 6V to the servomotors. It includes a voltage regulator that will supply 3V back to the micro:bit, so that you don’t have to power it separately.

Features

  • Header pins for three servo motors
  • Up to 2A total can be supplied to the servo motors
  • Regulated 3V output to power your micro:bit
  • Polarity protection for the servomotors
  • Electrolytic reservoir capacitor for the servomotors
  • 1kΩ series resistors to the control signals to prevent accidental sort-circuits of the micro:bit’s output pins.
  • Orange LED to indicate that the Servo for micro:bit board has power.
  • Compatible with micro:bit v1 and v2!

Connections

The picture below shows a typical setup using the Servo for micro:bit board.

The following connections have been made:

  • 3 x servomotors plugged into header pins. These need to be the right way around, with the control signal (yellow or orange wire) to the left (pins marked c).
  • Alligator clip lead from GND on the micro:bit to GND on the Servo for micro:bit board.
  • Optional alligator clip lead from 3V on the micro:bit to 3V on the Servo for micro:bit board. You only need this if you want to power the micro:bit from the same battery pack as the servomotors. If you want to power the micro:bit over USB or the JST battery connector then you do not need this connection.
  • Alligator clip leads between P0, P1, P2 on the micro:bit to the Servo for micro:bit board. These need to match up with the servomotors you are using, so if you only need the board for one servomotor, then just connect P0 on the micro:bit to P0 on the Servo for micro:bit and make sure that there is a servomotor attached to the header pins marked 0.
  • Power to the screw terminal on the Servo for micro:bit. Typically this will be a 4xAA battery pack or other power supply. Make sure that the positive lead goes to the screw terminal marked with a +

Test Software

To check that everything is working, this Blocks code project will get you started. Flash it onto your Servo for micro:bit and the servo arms should all start waggling in a random manner. You can see a video of this in action here.

The servo write pin block allows you to set the angle of the servomotor’s arm between 0 and 180 degrees. Note that servomotors, will not usually travel a full 180 degrees so you may find the actual range is more like 10 to 170 degrees.