Circuits

Dough Circuits: LED Caterpillar

Build a circuit with play dough, LEDs and a 9 volt battery.

A completed dough caterpillar with four LEDs lighting up between the different colored sections of dough.
Make an LED Light-Up Caterpillar with conductive dough, a battery and some creativity!

What do you get when you combine a love for kids dough projects with some basic electronics? An LED light-up caterpillar, of course! This fun project, inspired by ELI the robot's adventure, is a great way to introduce your kids to the world of circuits. The best part? It uses a special ingredient: conductive dough!

That's right, certain types of dough, like play dough and salt dough, can conduct electricity, making it the perfect material for a circuit.

Let's get started on this simple and engaging project.

You can also watch a quick tutorial on YouTube!

Youtube Caterpillar Tutorial

Gather Your Supplies

First, you'll need a few items to bring your caterpillar to life.

  • Play dough or salt dough in various colors
  • Several LEDs (light-emitting diodes)
  • A 9-volt battery
  • A 9-volt battery lead (optional, but makes it easier)
A variety of supplies, including different colored dough, a 9-volt battery, LEDs, and a battery lead.
Your supplies include different colored dough, a 9-volt battery, LEDs, and a battery lead.
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This project uses 9V batteries and small, simple electronics parts and is best completed with a trusted adult!

Connect the Battery

You've got the power! If you have a battery lead, attach it to the terminals of the 9-volt battery. If you don't have a lead, you can stick two separate pieces of dough directly to the separate battery's terminals, leaving them disconnected for your project for the moment.

ELI's robot hand connecting the battery lead to a 9 volt battery
Attach the battery lead (optional)

Shape Your Caterpillar

Now for the fun part: creating your caterpillar!

  1. Take your dough and roll each color into a ball.
  2. Line them up to form the body of your caterpillar. Make sure each piece of dough is touching the next one. This contact is important because it allows the electricity to flow from one piece to the next.
  3. Leave gaps between the pieces you want to bridge with LED lights.
Different colored dough balls lined up to form a caterpillar's body.
Roll out your dough
Rainbow colored balls make a caterpillar shape with some pieces touching to conduct
Shape your caterpillar, with some pieces touching

Add the Power

With your caterpillar shaped, it's time to bring in the power source.

  1. Poke the black wire from the battery lead into the first piece of dough.
  2. Poke the red wire into the last piece of dough. This creates a path for the electricity to flow through your caterpillar's body.
The black lead is connected to the front of the caterpillar dough, and the red lead to the back of the caterpillar dough.
Poke the battery leads into the start and end of your caterpillar creation

Bridge the Dough Circuit with LED Lights

Now for the main event—adding the lights!

  1. Look closely at an LED. You'll notice it has two wires, or leads: one is shorter than the other. The shorter lead is the negative side and the longer one is the positive side.
  2. Gently pull the leads apart to create a wider gap.
  3. Place your first LED across the gap between the first two pieces of dough.
  4. Gently push the leads into the dough so they are firmly in place.
  5. Repeat this for the other sections of your caterpillar.

As soon as your circuit is closed from the battery, through the LED, and back to the battery, you should see your lights powered!

Closeup of a red LED with a short and long metal lead.
Each LED has a short and long metal lead.
A red LED is inserted between each gap in the dough, completing the circuit
Bridge each gap in your dough circuit with an LED

Light It Up!

When you're finished, your LED lights should come on, and your caterpillar should glow!

A completed dough caterpillar with three LEDs lighting up between the different colored sections of dough
A completed LED Caterpillar

Troubleshooting Common Problems

If your lights don't turn on, don't worry! This is part of the fun of working with circuits. Think of yourself as a "bug detective" and try these steps to debug your bug. See this post if you're struggling:

Dough Circuits: Debug Your Bug
Adventures with ELI
Infinite Retry LabsELI, Robot Companion

Share Your Creations!

This project is a great way for children to learn about simple circuits, conductors, and how electricity flows. Plus, they get to build a cool, glowing caterpillar!

Did your caterpillar light up? We'd love to see it!

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Share your prints with the AWE Community!
Use the hashtag #AWEProjects to share your project results!
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Don't Forget! Don't forget to clean up your project and put your materials away when you're done. This includes disconnecting your battery from the leads for safety and storing it with your other household batteries!
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