What can you do with an old hard drive other than discarding it? You could build a clock with it. We have covered a bunch of cool hard drive clocks in the past. This guide shows you how to use an old HDD to build a 3D POV Clock. The device spins a set of LEDs really fast to show you time. You will need to need a HDD, power supply, QTI sensor, and an Arduino Uno to get started:
mso797 has been kind enough to include the instructions and parts on Instructables.com. What do you think? How would you improve this clock?