Proto G Engineering is known for making a wide array of interesting electromechanical projects, and his recent license plate spinner looks like something straight out of a James Bond movie. The device holds four license plates on a stand, which are rotated into place using a pair of brushless gimbal motors.
The purpose of the spinner is (supposedly) to use in a showroom display that shows off a license plate recognition system. Control is via an ESP32, along with an ODrive motor control board. A pair of gimbal motors situated on each side of the plate assembly turn the license plates, and while certainly not the cheapest option motor-wise they allow for direct drive and no need for a belt assembly to detract from the beauty of the rig.
Encoders are implemented to keep the motors synced up. These use a trapezoidal speed profile to allow the motors speeds to ramp up and down, stopping it in the correct position without a lot of wobble. While there are countless ways that such a task could have been done, the custom metal frame and low profile motor design looks like something that would work really well in a showroom… or secretly built into a car’s trunk for "other" uses!