Driving a dead disk’s servo arm

Despite the fact that they are, apparently more creative uses of a broken HDD’s (http://alan-parekh.com/projects/hard-drive-clock/) I decided to play around with my unit with an H-bridge. I programmed a small AVR microcontroller to generate short pulses of alternating polarity, to drive the coil under the arm one way and then the other. I found the solder joints on the drive’s PCB and attached the power to my driver unit, and the driver unit to the coil leads. This resulted in a mildly entertaining toy, depicted in the following movie. It served as an exhibit at one Science Festival, to demonstrate the inner workings of the components of a PC, in a somewhat unorthodox way.

Here is a photo of the opened disk:

Opened HDD