POV Clock Spins Light Filter Instead Of LEDs

This hard-drive based POV clock is a treasure trove of great design choices. Now, we’ve seen a bunch of spinning clock builds. Several of the hard drive versions use slits cut in the platters to create a display by illuminating an LED behind those slits at just the right moment. This is a similar idea but [Jason Hotchkiss] ditched the platters all together and replaced them with a light filter. The filter disc has digits 0-9 as well as a colon (not seen above because the colons blink each second). As this disc spins, the Arduino compatible controller lights up LEDs in the eight digital positions to illuminate the correct number.

The filter is made from an etched copper-clad disc. This is a great choice because the fiberglass substrate is strong, light weight, translucent, and available. The filter idea also means you don’t need to get power or data to a spinning platform. [Jason] has also designed a very impressive controller board that is the same size as the footprint of the laptop hard drive he’s using. Check out the video after the break to see his description of what went into the hardware choices he arrived upon.[youtube=http://www.youtube.com/watch?v=kPdYpST_yoE&w=470]

21 thoughts on “POV Clock Spins Light Filter Instead Of LEDs

  1. That’s pretty cool, and I like all the diy pcb’s he made. I wonder if he should be concerned about the “platter” flying apart at those high speeds, especially with the holes cut out and him moving it around in his hand?

    1. No, there aren’t any holes in the FR4 disk, just in the layer of copper, so its still a solid disk – I don’t think its going anywhere (Not like my other POV, which ejected a button cell into my thumb…). The edge of the disk isn’t samurai-sword sharp either, I actually touched it in the clip and didn’t even notice till I watched it back.

  2. Awesome project!

    I wonder if the disk would be better balanced if there were two sets of digits on it, each set using up one half of the disk so that each digit for one set would be opposite the same digit of the other set.

    I also wonder how hard it would be to put one “right side up” and one “upside down” set of digits on there, so you could use the bottom half of the disk to display the date…

    Of course, if you would have a “right side up” and “upside down” set, you would have a bit more space because the “right side up” 6 can be the “upside down” 9, and the 0 is also symmetrical. Hmmm…


  3. I think that this is one of the best designs I’ve seen here. You take a handful of very cheap or free items and make a beautifully simple, easy to read display. Simplicity realized is elegance!

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