Andy Geppert's Business Card Is Making Moves — As It's a Literal Brushless Motor

Designed for educational purposes, this compact card is a standalone motor complete with driver and on-board microcontroller.

Gareth Halfacree
19 days agoHW101

Mechatronics engineer and maker Andy Geppert has built a business card that's also a fully-functional brushless motor, complete with driver.

"Designed for learning, this electronic business card PCB will guide your build of a brushless motor and provides the opportunity to experiment with control algorithms," Geppert explains of his creation. "Try delta and wye winding configurations and experiment with rotor and magnet designs as much as you want. The circuit is illustrated with test points on the front side, and the components are all placed on the back side."

While the PCB Geppert has designed manages to fulfill the requirement of a business card by including his contact information, it's crammed into the bottom-right — making room for the more important visual: a schematic of the circuit designed into the board which doubles as an illustrated guide to its test points.

Next to the schematic is a cut-out with T-shaped protrusions: the coils, which are designed to be wound by hand. A rotor can then be installed in the center of the cut-out — and, through the board's built-in driver, be convinced to turn. Different winding configurations can be selected through solder jumpers, and there's voltage feedback-based motor phase position sensing using the analog comparators on the board's Microchip ATmega328PB microcontroller.

A motor with an exposed rotor floating in the middle of a cut-out in a business card-sized circuit board isn't the most practical way of turning electricity into motion, but Geppert is hoping the device will prove handy for educational purposes — though, at the time of writing, the design was still a work-in-progress.

"The rotor moves a little bit with manual voltage pulses," Geppert explains, "but the small brushless motor driver I tested with can't get the rotor to turn. There is a lot of room for testing and optimization. Gaps, flux density, coil and magnet coils… guaranteed learning of one kind or another awaits me."

The project is being documented on Hackaday.io, while design files and source code have been published to GitHub under an unspecified license.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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