5400RPM Hard-Disk Clock

The Harddrive clock works using the principal of 
Persistence of Vision, It really stands out in the dark.

What is it?

This a project that utilizes the common computer Hard-disk in an uncommon manner. The device uses stock high RPM hard-disk components in conjunction with an RGB LED strip to draw what becomes a clock face using the principals of Persistence of Vision. Check out the video below, it is a bit noisy:

How does it work?

1.      The hard-drive platter (upon which data was stored) rotates at approximately 1 rotation every 10 milliseconds. A slit has been cut in the platter which light shines through.
2.      A magnet placed opposite the slit times each rotation so that the clock face can be mapped.
3.      A strip of high-output RGB LED’s below the platter turn on and off very quickly at the precise moments needed to draw the clock face. This is facilitated by the rotation time.


- Buttons for setting the time and changing display modes
- Demo modes, accessible via the mode button
- A Serial Input mode which reads pages from the computer over USB
- Can be used with external programs over a virtual COM port to display Health, Ammo, Volume, Song playtime, etc.
- Disk is timed using a Hall Sensor for viewing without obstructions.
- Design reduced vibration and noise via a sealed case.


I would like to thank Giles Hall, who was kind enough to provide open source Arduino Code which taught me about the speedy ISR routines and timers that got me to finally read that Arudino datasheet.
His project can be found here. I would also like to thank Ian of www.ian.org for documenting his clock on his website.

Continue on to the Build Process
Download the Source Code

Subpages (2): Build Process Source Code