Self-Balancing Unicycle

Bikes Craft & Design Fun & Games
Self-Balancing Unicycle

Achieving Balance

By Laura Kiniry

Photos by Rachel Fong

Tired of walking to the supermarket from his dorm, 21-year-old MIT computer science and electrical engineering student Stephan Boyer decided he needed a quicker way to travel.

“I wanted a personal transporter that could get me around campus but be as small and light and fast as possible,” he says. Five months later, Boyer had Bullet, a self-balancing electric unicycle that reaches a top speed of 15 miles per hour and is the envy of his peers.

Boyer built Bullet with $1,000 and endless ingenuity. After teaching himself welding and some mechanical engineering, he got to work collecting materials: a basic fork to hold both a moped wheel and motor, welded-on pedals to provide foot support, and a top seat. “I didn’t really plan out the [entire design], so the battery and electronics are held on with zip ties,” he says. Bullet also features a kill switch for swift deactivation. He says the design could be built for $600.

For balance, Bullet employs an onboard computer and two sensors: a gyro and an accelerometer. The former measures Bullet’s rotation speed and the latter determines its acceleration due to gravity. Using this data, the computer can detect the angle of the unicycle and prevent it from leaning too far forward or backward.

“Because Bullet only has one wheel, you still have to balance side to side,” says Boyer, who does this by twisting his hips to turn and occasionally flailing his arms for stabilization, in the same way a flying squirrel uses its tail. Riding it several miles daily, Boyer became somewhat of a pro at handling the vehicle, but he stresses that it takes both skill and patience. “My number one rule when riding Bullet is that things in the road are always bigger than they appear.”


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10 thoughts on “Self-Balancing Unicycle

  1. Marcelo Fornaso says:

    See a better one here: http://marcelo.fornaso.com/tilto/
    Cheers!

    1. Michal Dobrzynski says:

      You do realise that a unicycle can’t have more than 1 wheel right?

  2. Self-Balancing Unicycle | A Maker's Dream Factory says:

    […]   Makezine VN:F [1.9.20_1166]please wait…Rating: 0.0/5 (0 votes […]

  3. 自平衡独轮脚踏车 | 开源硬件和机器人梦工厂 says:

    […]  Makezine VN:F [1.9.20_1166]please wait…Rating: 0.0/5 (0 votes […]

  4. Ann Christine says:

    That’s a nice little toy but if you want to see the most advanced Self-Balancing Electric Unicycle EVER produced, then check out the EcoBoomer iGO here: http://EcoBoomer.tv and let us know what you think. You will see that compared to the EcoBoomer iGO these other electric unicycles seem very low grade and a bit amateur, but that’s just my opinion. Waiting for your feedback. =)

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