How to Make a Bristle Bot: A Simple STEM Robot for Kids

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Looking for a fun and easy robotics project for kids? A bristle bot is the perfect introduction to STEM and simple circuits. Made from a toothbrush head and a few basic electronics, these tiny vibrating robots are surprisingly entertaining — and educational too!

This project is ideal for science lessons, homeschool STEM units, classroom makerspaces, or just a rainy afternoon of hands-on fun. It also is a great activity to use for a Wild Robot book club!

We made our bristle bots this week at a Wild Robot book club for my daughter and her friends (ages 9-11). It paired perfectly with that! See the end of the post for more ideas to use this at a book club!

What Is a Bristle Bot?

A bristle bot is a tiny robot that moves using vibrations from a small motor. The bristles of a toothbrush act as little legs, and as the motor vibrates, it scoots the bot across a surface. While simple, bristle bots introduce kids to important scientific concepts:

How circuits work
Cause and effect
Engineering design
Vibration and motion

Supplies Needed:

1 toothbrush (preferably with angled or firm bristles)
1 button cell battery- We used these: LR44 1.5V
1 small vibration motor – We used these: DC3V 1200rpm
Double-sided foam tape
Scissors or pliers to cut the toothbrush head. (I actually used my garden shears!)
Optional: googly eyes, pipe cleaners, markers for decorating

How to Make a Bristle Bot

1. Prep the Toothbrush

Use scissors or pliers to cut off the head of the toothbrush, keeping only the bristle part. This will serve as the base of your bot.

2. Attach the Motor

Stick your small vibration motor to the top of the toothbrush head using a small piece of double-sided tape or hot glue. The motors we used had a sticky side that stick it right to the toothbrush without any extra adhesive. Position it slightly to one side to help with directional movement.

3. Connect the Battery

Tape the coin cell battery to the motor. Touch one wire from the motor to the positive side of the battery and the other wire to the negative side. It should begin to vibrate! You can secure the wires in place with more tape or glue if needed.

Tip: Only connect the battery when you’re ready for the bot to move, or add a simple switch mechanism to control it.

4. Decorate Your Bot

Make your bot come to life! Add googly eyes, draw on a face, or use pipe cleaners to create legs, antennae, or arms. Kids can customize theirs with unique personalities.

This one got a tail and it actually stabilized it really well! She also decorated the handle of her toothbrush to match! 🙂

Watch our Bristle Bots in Action:

The Science Behind It

The vibrating motor causes rapid movement, and the angled bristles convert this vibration into directional motion. The design teaches about:

Electrical circuits – Battery + motor = energy source + load
Engineering – Adjusting placement of parts changes movement
Physics – Vibrational energy transfers to motion

Experiment Ideas

Want to make this into a full STEM lesson? Try these:

Race your bots – Whose bot goes fastest? Straightest?
Change the bristle angles – How does that affect movement?
Add weights – What happens if you tape on a paperclip or coin?
Build an obstacle course – Can your bot make it through?

I love this busy messy shot of the girls creating their bristle bots! They were having so much fun & got extra creative with their designs.

Can You Paint with a Bristle Bot?

Yes — and it’s awesome! Turn your bristle bot into a painting machine by attaching a small sponge, cotton ball, or pom-pom under the bristles. Dip in washable paint and let it wiggle around on paper, leaving wild, colorful trails.

Try using multiple colors and having bots cross paths
Use large butcher paper to make collaborative artwork
Add a design challenge: Can your bot draw a circle?

This turns a fun STEM activity into a full STEAM experience!

Bristle Bot Troubleshooting Tips

If your bot isn’t working quite right, here’s how to fix it:

My bristle bot keeps tipping over

Center the motor and battery for better balance
Use firmer bristles or trim the ends for more stability
Try it on a smooth surface like poster board
Add a toothpick or straw “tail” to help it stand upright

It won’t move!

Check wire connections — are they touching the battery correctly?
Try flipping the battery if the motor doesn’t vibrate
Make sure your motor isn’t stuck or clogged with glue

It moves in circles or backwards

Try repositioning the motor slightly off-center
Experiment with trimming bristles at different angles
Adjust weight balance between the front and back

Troubleshooting is part of the engineering process! Encourage kids to tweak and test to discover what changes improve performance.

Bristle bots are an easy, budget-friendly way to introduce kids to robotics and engineering. Whether you’re teaching a science unit, hosting a STEM club, or just exploring at home, this tiny robot will bring big learning and lots of giggles!

Also find this video on YouTube:

See More STEM Activities for Kids:

Building Electric Circuits: STEM Challenge Cards

200+ Exciting Elementary STEM Projects

STEM Toy: Penny Spinners

Origami Firefly Paper Circuits

Wild Robot Book Club Ideas:

For Our Wild Robot Book Club:

We started with a discussion of our favorite parts of the book. I also had the girls share what type of robot they would be or have if they could choose.

Next we made the bristle bots. They were a huge hit with these girls (ages 9-11)

After that we did an Egg Drop Challenge (to protect Brightbill’s egg),

And finally, we made robot snacks using different shapes of crackers, peanut butter, pretzel sticks, chocolate chips, and raisins/craisins.