Micro:bit Servo Animals

What you will need
  • BBC micro:bit
  • Micro USB cable
  • Battery pack with 2 x AAA batteries
  • 1 x Servo
  • 3 x Breadboard jumper wires
  • 3 x Crocodile clip leads
  • Optional: Battery pack with 3 x AA batteries 
Step 1
  • Download and print one of the following templates (or create your own).

Cats & Dogs:
servo_animals.pdf
File Size: 295 kb
File Type: pdf
Download File
Gruffalo:
gruffalo.pdf
File Size: 177 kb
File Type: pdf
Download File
Step 2 - Assembly
  • Attach the tail (or piece that will move) to the arm of the servo using tape or blu tack etc.
  • Use a pencil (or pen) to make a hole where the servo attaches to the tail.
  • Insert the servo (arm connector) into the hole and attach the servo arm to the servo. See image (right). 
  • Attach the servo to the back of your card animal using tape.
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​​​Connecting a Servo to a micro:bit
Instructions on how to attach a Servo to the micro:bit.
Servo

Wiring instructions
  1. Disconnect the micro:bit from your computer and disconnect the battery pack.
  2. Insert the jumper wires into the servo plug. See figure 1. (if you don’t have a black, red or orange jumper wires, you can replace these with any colour you wish as long as you remember which jumper wire is connected to which lead on your servo!)
  3. Connect the crocodile clips to the corresponding jumper wires:
    1. Brown to GND pin.
    2. Red to 3V.
    3. Orange to Pin 0.
Connecting an external power supply to a servo

Whilst these micro-servos can work with the micro:bit, the specified operating voltage for most servo motors is around +5V and that the micro:bit can only supply a small amount of power to connected circuits (3V and 90mA V1 and 190mA V2max). Trying to draw more power than the micro:bit can safely supply, could lead to damaging the device.

For micro:bit V1, the most reliable way to use this type of servo is to power the micro:bit via a battery pack and to use fresh batteries, as the battery voltage drops the servo will become less reliable.
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​Connecting an external power supply to a servo
The optimal method for connecting a servo is to use a separate battery pack to power the servo and use the micro:bit to control it. This way you are only connecting Pin0 and GND from the micro:bit to the servo (we still need to use GND to share a common ground with other parts of the circuit). 
WARNING! The external battery pack supplies a higher voltage than the micro:bit. Do not connect the positive (+/red) wire from an external battery pack to the micro:bit as you will damage it.

For more guidance on connecting servos to the micro:bit, check out the official help guide: Using a servo with the micro:bit : Help & Support (microbit.org)
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​Programming your Servo Animal
Copy the below:
To access the 'Pins' blocks, click on 'Advanced'.
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​Testing your code
  1. Download your program to your micro:bit.
  2. Reconnect your battery and run your program.

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