HDDJ – hard disk for rotary input

Computers & Mobile
HDDJ – hard disk for rotary input


In search of smooth-spinning hardware to use as a rotary input device, nvillar made use of an old hard drive – resulting in a sweet controller with excellent aesthetics –

We admired the quality of the bearings in the motor that drives the disk plates, enjoyed the fact that even a soft flick would get it spinning for a long time, and wondered whether we could sample an output from it when it was spun by hand, in much the same way that an electric motor, when turned, acts as a dynamo and outputs a voltage.

The answer is yes – and it’s a very simple process to turn a hard disk into a rotary input device that has some unique properties. All you’ll need is an old hard disk drive, a few op amps, resistors and a programmable microcontroller of some kind.

Nice pushbuttons! See the instructable for all the project deets – HDDJ: Turning an old hard disk drive into a rotary input device [via Hack a Day]

4 thoughts on “HDDJ – hard disk for rotary input

  1. Simon says:

    Cool! Must be hell for fingerprints though!

  2. anachrocomputer says:

    I’ve just built a working prototype of a gadget inspired by this, but using a CD-ROM drive motor instead of a hard disk drive motor. Most of the HDDs that I had already dismantled only brought out three wires from the motor, which made me think about other brushless DC motors. CD-ROM drives and VCR head drum motors, in fact. That led to a design based on the three hall-effect sensors that are normally used for commutation, plus three comparators (TLC3704 chip). It works, so now I need to interface it with an AVR chip.

Comments are closed.

Discuss this article with the rest of the community on our Discord server!


Maker Faire Bay Area 2023 - Mare Island, CA

Escape to an island of imagination + innovation as Maker Faire Bay Area returns for its 15th iteration!

Buy Tickets today! SAVE 15% and lock-in your preferred date(s).