A robot that can move in any direction immediately is useful for getting around tight spaces and for behaviors like chasing (or fleeing). No matter how fast an R/C car is, there’s no way it can catch something that can instantly go any direction, even sideways. Regular car-style robots can’t drive sideways, but omniwheel robots can!

An omniwheel is a wheel whose tread is made up of a bunch of little rollers. They’re used commercially for things like transfer tables on production lines, and this means they’re cheap and reliable. In this project you’ll use them to build a Kiwi drive robot platform — a three-omniwheel vehicle that can travel in any direction. It’s mesmerizing to watch, and it can even rotate while traveling, so it’s great for turret-type applications too.

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If a robot can drive in any direction immediately, it is called holonomic — it has two degrees of freedom on the floor. Cars, where all the wheels line up, can’t move at right angles to their wheels, so they’re not holonomic.

Omniwheels can move at 90 degrees to their axis, so you can mount them facing different directions on your vehicle and use a bit of math to still go in a straight line. (That’s where a microcontroller comes in handy.) Like most things in engineering, there are some tradeoffs, which is why we don’t all drive omniwheel cars. They’re slower, sensitive to dust, can take less load — only a few pounds for the wheels we’re using — and they’re less efficient. But in tight spaces they’re the right choice, and a lot of fun!

Our omniwheel robot is a beginner-friendly build that uses an Arduino microcontroller, the new Make: Motor Shield, and standard R/C gear — all of it plug-and-play.

NEW! Make: Motor Shield

Co-developed with Wicked Device, our awesome new motor shield can run 4 DC motors (1.2A–3A max), or 2 steppers and 6 servos. It has current sensing so you can use motors as sensors, and it accepts R/C inputs from standard radio control gear! No soldering required. Maker Shed item #MSMOT01, from makershed.com.