This past World Maker Faire was a blast, we did Battle Bots and it was a huge success. Families, students, and teachers were engaged and spent a great deal of time building bots, making obstacles, and battling it out. The one thing about the activity that we got tons of questions from educators was how did we make our magnetic motors. So we made a step by step tutorial to show how we modified our motors plus some extra information on how to scale it for various grade ranges.

For this tutorial we will:

  • Review Materials and tools needed.
  • Go over how to modify the motor mount.
  • Explain how to connect your motor to the motor mount.
  • Let you know how to reinforce your motors to make them more resilient.
  • Show you how to connect the magnets to your motors.
  • Give you tips, tricks, adaptations, and adjustments for using these motors with different age groups.

Build time: About 10-15 minutes per motor, depending on how streamlined your process is.

 

Materials for Quick Connect Motors

  • Mini electric motor with mounts. We chose these particular motors because they came with a ready-made mount, which will save some building time for your students and lets them get straight into design.
  • Ceramic ring magnets. This is the material we strongly recommend for younger children. Alternatively, you may wish to go with stronger “rare earth” neodymium magnets.
  • A vice grip or some clamps.
  • A heat shrink kit. We experimented with several sizes from this set.
  • An electric drill with a 3/16 or equivalent drill bit.
  • A hot glue gun.
  • A lighter (or optionally a heat gun).

Attention: educators, museum personnel, and parents should exercise all reasonable caution when introducing children to activities with strong magnets and electricity. This activity includes both.

Once your materials arrive, follow the next few steps to make them ready for your students to use in their robots.

 

Modifying the Mount

Once the motors have arrived, remove the white plastic mounts and prep them for modification. You’ll need to drill three holes to improve these mounts and make them better for the students. Have ready a vice grip or clamp, and an electric drill with a 3/16 inch (or equivalent) drill bit.

Drill three holes in your mount: two on either side of your mount, one in the center as indicated in the image above.

The two holes on either side of the mount are for the positive and negative wires to come through. The hole in the center is for using craft wire, pipe cleaners or string to attach your motor to the body of your robot.

 

Attaching the Motor to the Mount

Once you have the holes drilled mount your motor as indicated in the images for this step, and wrap the positive and negative lines through the outer two holes. It is important that you wrap the wires to protect the relatively weak solder points at the back of the motor. If a student were to pull on the wire directly the solder point would break and the wire would come loose. In this configuration, the force of that same pull is directed to the mount which absorbs the force and reduces the risk of a motor coming apart. Less repair time = more awesome making time.

Once you have your motor mounts prepped and loaded, we recommend using hot glue to give it that one last layer of security.

Now you should have a resilient, mountable motor, with two wires coming out of the back. In this step we’ll be adapting the wires using ring magnets, to make them easier for kids to prototype their ideas.

First, use wire strippers to take off about an inch and a half of insulation from the two wires coming out of the back of your motor.

Now apply a sheath of heat shrink to each wire.

Once you have the heat shrink on, wrap the wire around the ring magnet and twist it to secure.

Apply a small point of solder to the wire below your magnet, to ensure it stays put.

Now slide the heat shrink up to cover the exposed wire to the base of the magnet.

At this point, you can start to line up the motors you are making by hanging them on a metal surface. Once you have them all done you can take a heat gun and run it slowly down the line until all of your heat shrink is tight around your wires. It’s very satisfying.

If you don’t have a heat gun you can do this last step one at a time with a lighter. Still just as satisfying.

If you have followed the steps so far you should have a motor ready to use with your kids, just attach the magnets to the positive and negative terminals of a(n) AA battery and watch it go!

 

Some Tips and Tricks

You may at this point be wondering what that middle hole is for. Kids can use this hole and a pipe cleaner, or craft wire, to attach their motor to a surface.

Some younger kids who are making bots that move via vibration, may not have the skill or patience to put an eccentric wobble on their motors by themselves. In this instance, you should probably put one on each motor for them. We recommend a piece of hot glue or a wine cork.

For storage or during activities, you can hang these motors like chili peppers by hanging them on a metal surface.

 

Adaptations and Adjustments for the Classroom

Design Lab knows that not every class is the same, and that every activity can and should be adjusted by the educator for their particular group of students. For this, we have some adaptations and adjustments. I have broken this into sections for Older Students (middle school – high school) and Younger Students (pre-k – elementary).

 

Older Students

For older students, you may not need to wrap the wires and glue the motor into the mount. This could give them more freedom to use the motor in more complicated ways or to use the large vertical hole in the motor mount before inserting the motor.

You might want to try using the stronger “rare earth” magnets I mentioned in the materials list for this activity. These magnets are extremely strong and small, making them hard to disconnect from the battery via vibrations, and therefore ideal for this activity. Warning: All due caution should be observed when exposing students to strong magnets and electricity. If these magnets are swallowed there is a real possibility of injury and death. Do not expose your students to them if there is a risk of ingestion.

Try introducing wire extensions, included in the step images. This adaptation could allow students more freedom to innovate by daisy-chaining batteries together, extending the length of their bot, or even looping in makeshift switches and maybe even adding in real switches. Warning: If students connect the positive and negative terminals of a battery together using wire extensions the battery will heat up dangerously.

 

Younger Students

For children below five, we suggest structuring the activity more around making the battery connection and experimenting with the spinning motor.

Have soft materials like craft foam to attach to the motor rods available. Attaching craft foam to a motor they connected themselves is also very rewarding.

Have the students mount their motors to surfaces using clay or sticky tack, careful not to get it clogged in the motors moving parts.

We also had a lot of fun using this same magnet method to adopt more complex motors. Just remember to protect the wires by wrapping them in some way, and to use hot glue when necessary to keep your motor resilient to wear and tear. You’ll appreciate that you did.

 

Get Creative With It!

You can find these interesting motors in a lot of different places. We suggest finding discounted or used toys and sourcing for parts. Older students may even like to join in.

You can also view these tutorials on instructables.com. Stay tuned for how to build and modify parts to create Battle Bots, including large Destructor Bots!