Hardware hacker Ian Matthew decided to see if he could turn a hard drive into a clock. But this isn’t one of those lazy designs where you just stick some clock hands through a hard drive platter. On the contrary, Ian went way over the top.
A narrow slot cut into the platter allows a set of flashing colored LEDs to show through as it spins. It’s powered by a PIC18F252 controller, along with custom software which adjusts the LED patterns accordingly.
A small magnet on the platter triggers a magnetic switch to let the system know when a rotation is complete. The spinning drive platter not only can display the time, it creates a wondrous light show when it’s not in clock mode. (Ian got his inspiration from a similar clock design by Alan Parekhs).
According to Ian: “The clock works because the human eye does not see frequencies above 60 or so as blinking, but as a solid color. This is how we see a TV picture as a full image and not a series of lines being drawn across it. At 5400 RPM this drive spins just over 90 times a second, plenty fast enough to fool the eye into thinking it sees solid hands and not a spinning bar of light.”
I used to think this was the best hard disk clock hack, but I think we have a new champion.