Channeling his inner Gru, YouTuber Electo built a robotic minion army to terrorize and amuse the public in local shopping malls.

Building one minion robot is, in theory, pretty straightforward. That is especially true when, like these, that robot isn’t actually bipedal and instead rolls around on little wheels attached to the feet. But creating 10 robots is more of a challenge. Assuming a limited budget, the robots would have to be relatively inexpensive. So, how could Electo give them the ability to run around causing mayhem?

Electo’s solution was to make one smart minion, called King Bob, to lead all of the other minions of lesser intelligence. The basic design consists of an Arduino that controls the two drive motors and that can communicate with other Arduino boards via radio transceiver modules. Those components fit inside a 3D-printed shell and this basic minion is pretty affordable to construct.

But King Bob has more advanced hardware and special abilities. He can receive explicit movement commands from Electo’s radio transmitter controller, but also has some intelligence thanks to a single-board computer and a camera. That lets it run a computer vision application to detect and follow specific things that it sees. In this case, that is a banana.

King Bob could follow explicit commands or a banana, but what about the other minions? Electo gave them the ability to follow their leader by simply mimicking its movements. Any movement that King Bob makes is also transmitted over radio to the other minions, so they can make the same movements. This is intentionally clumsy (because minions), but lets the group move together in an entertaining way as they traverse shopping malls and movie theaters.