Looking for a way to get kids designing and building their own simple robots? With just a Circuit Playground Express (CPX), a servo motor, and a few household materials, anyone can create a Cardboard Inchworm that meets the "sense-think-act" definition of a robot! Here's how:

  • The Cardboard Inchworm can sense a loud sound using the audio sensor (microphone) built into the CPX.
  • Then it can think about how to react, thanks to the CPX's powerful microcontroller brain.
  • Finally, it can act by triggering the servo motor to repeatedly pull the front and back of the Inchworm together and letting them slide apart, creating a slow but steady crawling motion. 

The Inchworm is quick to build, and Microsoft MakeCode makes it super-easy to program! And it also lends itself to multiple variations in materials and structure. See if you can figure out how to make your Inchworm go even faster and crawl over more kinds of surfaces!

When you're done, it's also easy to remove the CPX and accessories and use them in another project. The rest of the Inchworm can be recycled. That's why programmable cardboard robots are a great first electronics project for kids and beginners!

Parts List -- Electronics

The Circuit Playground Express Base Kit is a good choice for this project, because it comes with the USB cable to program the board, a battery holder, and three AAA batteries. Or, to get all the electronics you need for this project (plus many more beginning robotics activities), get the Bots! book and parts bundle. You can also buy the Circuit Playground Express and accessories separately.

1 x Bots! by Kathy Ceceri - Book and Parts Bundle
We wanted to offer a pack that has everything you need to follow along the book and complete the projects. Many of the parts included are common, re-usable components, so you will be able to build on what you've learned and come up with new inventions!
1 x Circuit Playground Express - Base Kit
Circuit Playground Express is the next step towards a perfect introduction to electronics and programming. Kit includes the Circuit Playground Express, USB cable - A/MicroB, 3 Alkaline AAA batteries, Battery Holder, and a Mini Storage Box.
1 x Circuit Playground Express
Circuit Playground Express is the next step towards a perfect introduction to electronics and programming.
1 x USB cable - A/MicroB
Your standard A to micro-B USB cable, approximately 3 feet / 1 meter long
1 x 3 x AAA Battery Holder with On/Off Switch and 2-Pin JST
This battery holder connects 3 AAA batteries together in series for powering all kinds of projects.
1 x Alkaline AAA batteries - 3 pack
Battery power for your portable project! These batteries are good quality at a good price, and work fantastic with any of the kits or projects in the shop that use AAA's.
1 x Micro Servo
A tiny little servo that can rotate approximately 180 degrees (90 in each direction).
1 x Small Alligator Clip to Male Jumper Wire Bundle - 6 Pieces
These compact jumper cables have a premium male header on one end and a grippy mini alligator clip on the other.

Materials List -- Household and Crafts Supplies

Other supplies you will need include:

  • 1 strip of sturdy cardboard roughly 14 inches by 4.5 inches -- thin corrugated cardboard works well
  • masking tape
  • adhesive dots -- extra strength is best
  • peel-and-stick Velcro dots
  • 1 large metal paper clip
  • (optional) googly eyes

This guide was first published on Oct 25, 2018. It was last updated on Sep 27, 2023.

This page (Overview) was last updated on Oct 18, 2018.

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