Gyrocar

By Matthew Gryczan
Category: Electronics
Time Required: 10 to 12 hours
Difficulty: Easy

Anyone who’s played with a gyroscope toy powered by pulling a string wound around its axle knows that it’s fascinating, but also frustrating because it runs down so quickly and has to be rewound.

I decided to make an electric version that runs for as long as its AAA batteries hold out — which can be at least a half-hour, since the spinning gyroscope wheel stores some energy, easing the load on the motor.

I went through 3 iterations before arriving at this simple design, which is easy to build and works well.

In addition to battery power, the Gyrocar has a small track wheel at the bottom that’s friction-powered by the main gyroscope wheel.

The track wheel drives the Gyrocar along any thin, horizontal edge while it bears the gyroscope’s weight, but otherwise it doesn’t press against the main wheel, to avoid draining energy. Three screws let you adjust the track wheel or disable it entirely so that the Gyrocar stays idling in one place.

I’m sure MAKE readers will improve on my design. And if you’ve got access to a metal lathe, you can make an original version that isn’t based on the toy.

Parts
/
Tools

Switch, small (1) optional
Rod, Small plastic (1) optional; same diameter as the gyroscope axle
Wood glue (1)
Wood screws, small (5)
Sheet steel, 22 gauge (at least 2'x3') or brass
Tension roller, 1' diameter by 1/4' width, concave, steel (1) the kind for sliding doors, about $8
Machine screw, #10-32 x 3/8', with nut (2)
Machine screw, #6-32 x 3/8', with nuts and washer (1)
Plastic cap, round (1) or container; big enough to enclose the gyro wheel. Use a sealable storage container, or the cap from a spray can or detergent bottle. Cap sides should be straight, not tapered.
Battery, AAA (3)
Battery, AAA, with holder (3)
DC electric motor, Small, 4.5V or 5V (1)
Toy gyroscope, windup-style (1) or small metal wheel that can act as a gyroscope
Plywood, 3/16' (6'x6') or similar

Caliper or micrometer (optional)
Center punch optional
Drill bit a variety
Electric drill
Hammer
Hot glue gun optional
Lathe optional
Metal file or grinding wheel
Pencil
Pliers
Router or saw
Ruler
Sandpaper or rotary tool with sanding drum
Thread tap
Tinsnips
Try-square optional

Steps

Step #1: Make the motor assembly.

Trace around the plastic cap on the plywood sheet. Use a saw or router to cut out a disk that size, then file and sand it down until it fits flush just inside the cap.
TIP: If you use a hole saw, back the plywood with another piece of wood. This ensures that the saw won't rip the grain on the exit side, so the disk will have clean edges. A hole saw also drills a hole in the center, which is fine.
Measure the diameter of the motor, then scribe, cut, and sand 2 plywood rings whose inner diameters are just smaller than the motor and whose outer diameters are about twice the motor's diameter. File or sand the holes until the motor fits snugly inside. You can also cut a matching hole in the larger disk, which will give the gyroscope wheel more vertical space to fit inside the cap.

Conclusion

I've built a few Gyrocars with different designs. For one of them, I used foamcore board instead of plywood, which I covered with colored foil wrapping paper. I also covered the battery pack with a hemispherical spray-can lid, all of which gave the Gyrocar a flying-saucer look. I'd love to see your designs.

Related Posts on Make: Online:

DIY Electric Gyroscope

http://blog.makezine.com/archive/2006/11...

Gyroscopes: Everything You Need to Know

http://blog.makezine.com/archive/2006/03...

This project first appeared in MAKE Volume 23, page 84.