Arduino Hard Drive Clock by NatureTM


Long time Hacked Gadgets reader NatureTM has just completed phase 1 of his Hard Drive Clock. It’s using an Arduino to keep track of time and control the clock display LEDs. After accidentally letting out the magic smoke from the hard drive controller he decided to improvise and use a hobby RC motor speed controller. This clock will be super accurate when it is complete since it will eventually be using a Chronodot from Macetech.

Via: Hacked Gadgets Forum

“The first interrupt just records the time that the slot reaches the sensor and sets the position to zero. [It actually sets the position to the offset value since the sensor isn’t at 12 o’clock and I like to think of 12 as pos 0.] Now I can tell how long a rotation takes and how long it has been since the last completed rotation.

I have the rotation split into 180 divisions. I guess I’ll call them roxels (rotational pixels) since making up jargon is fun. I’ll call one full rotation of the platter a cycle. Then we know to draw the next roxel every cycle length/180. I then set arduino’s timer2 interrupt to overflow every new roxel and advance the roxel counter. I found this to be very efficient compared to other methods I tried. Actually, I was really proud when I figured this out, but I’ve been dying to know if everyone else is using this method as well. “

13 Comments


  1. Now I feel cool. 🙂 Just one thing I should have been more clear about: I used the hobby speed controller to control the HDD’s stock motor.

    Thanks Hacked Gadgets!


  2. Cool clocks for sure. I built 3 of them but could never get them to work correctly. I searched for 3 weeks trying to find anybody that could help but I guess these clocks are not that popular.

    Plus, nobody knew Alan’s Old School code. 😉


  3. Nice clock, I have been wanting to make one of these for ages, but couldn’t figure out the microcontroller stuff. Maybe with your description and some discussion I cna have another think about it.

    Good work.


  4. Thanks Andrew, I’d be happy to discuss it under my post in the hacked gadgets forum.

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