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Inchworm

Inchworm

Make a funny inchworm robot!

https://youtu.be/BiZLjugXMbM

Duration

3 Activities, approx 30-45 min each based on familiarity with the coding concepts.

Materials

  • Cardboard pieces (recycle!)
  • Glue gun or Tape (masking, duct tape, and/or packing tape)
  • Scissors that can cut cardboard
  • 1 micro:bit, battery holder and 2 AAA batteries
  • 3 Crocodile clips
  • 1 micro servo 9g SG90
  • 1 paper clip

Activities

Make

Turn a piece of cardboard into an inchworm! Duration: ~45 minutes

Materials

  • Cardboard
  • Scissors or cutters
  • glue gun or tape
  • 1 paper clip

Step 1: Cardboard

Cutout a cardboard rectangle. You can use the micro:bit as a ruler to figure out the size.

Step 2: Fold the middle

Make a fold in the cardboard right in the middle of the long side.

Step 3: Body arch

Make two smaller folds at the ends which lay flat on the ground. This is the base of the inchworm’s body.

Step 4: Front teeth

Fold in each of corner on one end of the cardboard. This is the front of the inchworm which will grip the ground.

Step 5: Back legs

Using scissors or a cutter (watch the fingers!), cut slits in the other end to make finger-like (these will be the actually) shapes. Fold one up, one down, and so on.

Step 6: Mounting the board

Using tape or a glue gun, mount the micro:bit on one side.

Step 7: Mounting the servo

Attach the servo (with tape or glue) on the edge of the other side of the cardboard.

Step 8: Cable clean up (optional)

Use tape to route the cables nicely on the inchworm.

Step 9: Attaching paper clip to servo

Unfold a paper clip and attach it to the servo arm.

Step 10: Attaching paper clip to cardboard

Slide the folded part of the paper clip into the cardboard and use tape to secure it. You might need to toy around with the size of the clip so that the servo rotation opens the inchworm sufficiently.

Step 11: It’s ready!

Your inchworm is ready!

Code

Add code to make the inchworm move. Duration: ~30 minutes

Step 1: walk forever

In order for the inchworm to move, the micro:bit needs to command the servo to move between 0 and 180 degrees at a certain pace. The code below starts the inchworm moving when the A button is pressed.

You might notice that the inchworm goes really slow or maybe just won’t move at all. Try to improve the design of your legs and teeth until the inchworm can go as fast as possible. Also, trying it on the carpet gives it more grip and helps to avoid skidding.

Connect

Remote control your inchworm with another micro:bit. Duration: ~30 minutes You will need one more micro:bit for this part. By using the radio, we can control the inchworm with another micro:bit. Download the code below to the micro:bit on the inchworm and then again onto a “controller” micro:bit. Whenever button A is pressed, the inchworm moves once.

Link: https://makecode.microbit.org/_WquHgcUXpXJT