Making the Light Monster

Let’s build the Light Monster for your Adafruit Circuit Playground Express!

Duration: ~1 hour

Step 1: Callibrating the servo motor (position)

Depending on the starting position, you’ll want to set up the servo horn so that it lies parallel to where the wires connect to the motor.

Incorrect examples

Ok, here’s the correct position:

Correct example


So, you want to set up the calibration in the beginning. That way you won’t have to worry about the motor position when you connect it to the head to create the jaw movement. After this step, temporarily disconnect the servo motor from the board.

Step 2: Preparing the body

Step 3: Preparing the head


After cutting out the head you can start working on cutting the teeth for the monster’s jaw!

Head with teeth

Step 4: Preparing the jaw


The second video shows how to cut the jaw to the correct shape.


Don’t forget about the teeth in the jaw!

Jaw with Teeth

Step 5: Connecting the jaw and the head

Step 6: Attaching the pipe cleaner to the servo motor

Step 7: Connecting the servo motor to the head

If hot glue works better for attaching the servo motor to the top of the head, go ahead and use it! In this video we used duct tape, which works just as well as hot glue.


When attaching the pipe cleaner to the bottom of the jaw, make sure you shape it so that the jaw stays closed.

Step 8: Connecting the head to the body

Step 9: Connecting the servo motor to Adafruit Circuit Playground Express


Make sure you do the two things listed here when you connect the servo motor to Adafruit Circuit Playground Express with the crocodile clips:

  • The GND crocodile clip should always be wired to the brown wire in the servo.
  • Make sure that your clips are in the right place. Since you will code your circuit playground to recognize signal to and from pin A2, attach the last crocodile clip to A2.

Step 10: Attaching the Adafruit Circuit Playground Express to the monster


Use tape if needed to secure any extra wiring from the crocodile clips to the servo motor.

Nice job! Now, let’s go on and make the code for the light monster…

NEXT: Code