Boys and homemade toy car

Homemade Toy Car: Turbo-charged Lego car

In this month’s post, we’ll show you how to build a homemade toy car by using the motors and propellers from a broken drone to power a Lego car.

For us, this project is more than just a fun rainy-day activity.

You see, among the list of first-world problems faced by our children, there are few that result in greater frustration or despair than when a favorite toy breaks.

Perhaps the fatal wound was inflicted mistakenly by the toy’s owner, by a careless visitor, by the owner’s sibling, or was simply a case of self-destruction. In any case, stomping, crying, and hurling of accusations ensue.

These days, we do things a bit differently. Broken toys are not such a big deal anymore.

The way we see it, after a toy breaks, you get to take it apart.

There are all sorts of interesting things you can learn by poking through toy guts. The best part is taking out the pieces that still work and creating something new out of them!

Our boys had this drone, which worked surprisingly well and survived many crash-landings. It was easy enough for our 4-year-old to control it, and both boys got a kick out of the 360-degree rolls it could do in the air. When one motor stopped working after many hours of use, we took out the other three motors and propellers to power a Lego car.

Here’s everything you need to get rolling.

You can check out our video tutorial here and subscribe to our YouTube channel to keep up with new projects.

The boys also built a wacky hack to surprise Dad. Everything is explained below as well (but we can’t give away the surprise!)

Supplies for the homemade toy car project

Motors and propellers from a broken drone, or you can purchase hobby motors and propellers

9-volt battery (this lithium 9-volt battery isn’t as heavy as a typical 9-volt battery, which could be too heavy for propellers to push)

Wire connectors or alligator clips

9-volt battery connector (optional)

Legos to build a toy car

Steps to build the homemade toy car

Step 1: Build the car

Step 2: Connect positive motor leads

Step 3: Connect negative motor leads

Step 4: Connect the battery leads to the positive and negative motor leads

Step 5: Attach the propellers to the car

Step 1: Build the car

If you want to build a fast car, you’ll want to build one that’s pretty small and light. If you’re using multiple propellers, it’s also helpful to use a longer horizontal piece to for attaching the propellers.

Lego car

Step 2: Connect positive motor leads

You’ll want to arrange the motors so that the positive leads of the motors are connected. You can use alligator clips or wire connectors to attach the leads together.

If you send electricity through a motor backwards, the propeller will spin backwards. The propeller blades are angled to exert more force in the forward direction, so they’ll power the car more effectively if they’re spinning the right way and all together in the same direction.

Here’s a drawing of how we wired the motors and battery together. We used a 9-volt battery.

Motors wired to battery

If you’re just using one hobby motor and propeller, you can just wire the positive wire from the motor to the positive end of the battery and visa versa.

Step 3: Connect negative motor leads

Now do the same for the negative motor leads– use alligator clips or wire connectors to attach the leads together.

Step 4: Connect the battery leads to the positive and negative motor leads

The easiest way to attach the battery to the motor leads is to use a battery connector with the 9-volt battery and to join the appropriate lead from the battery connector to each of the motor leads.

It is also possible to simply wind a piece of copper wire around each of the battery terminals.

Make sure never to create a direct path between the two battery terminals! The battery would drain and the wire would heat up.

Step 5: Attach the propellers to the homemade toy car!

We used tape to attach the propeller motors to the Lego bar. When everything is connected, let ‘er rip!

Propeller Car

If you want to have more fun with motors, check out Babble Dabble Do’s Steam Project: Tiny Dancers (A Homopolar Motor) and build your own simple motor (that dances, no less!).

And if you want to get even more inspired to take stuff apart, take a look at this post on Solar Energy for Kids: Reverse Engineering a Solar Powered Toy by From Engineer to Stay at Home Mom to see what you can learn about solar energy by taking apart a solar-powered toy.

Don’t forget to sign up for our free monthly newsletter to receive Geek Pack Hack updates along with an even wackier simple circuit project.

If you’ve built this project, have questions, or have suggestions for future posts, please let us know! We love comments.

Have fun!

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