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I've played with hard drive to make a clock but not like that. Mine has a slot in the platter and and the leds come on to show the leds threw the slot one color for hours and one for the mins. This is where i bet he got the idea. I had a site that showed this type spinning This one swings The magic wand clock: a Persistence of Vision toy !I bet I took a year to get the timing right I no you could do the math. But I still say it would take a long time to get it right.Here one like I made http://alan-parekh.com/projects/hard-drive-clock/
These are called POV (persistence of vision) clocks and there are loads of them out there. If you google POV clocks, or search POV on hackaday.com , I'm sure there's some decent guides or build logs. Usually, they just have a trigger on rotation. Count the time between rotations and you can calculate all of the LED timing from that.
Very impressive clock. If I were building this I would treat the display as a bitmap image and have 1 bit of ram per pixel. I would guess a resolution of 2 degrees would be enough and maybe 32 LEDs on the radius. This would require 4*180 bytes of ram and at 3,600RPM (60Hz refresh rate) the display would need refreshing at 60*180 = 10,800Hz or every 95uS. Possible to do with a pic running at 32MHz.
UTMonkey, if he spends the time balancing the PC board itself it'll be pretty quiet. One suggestion though, add a piezo buzzer for a tick noise, I imagine a spinning speaker is going to have some wacky phase shift effects.
that clock is awsome.
I did a search on web and saw a 3d globe done similar but the clock would be great if I knew where to obtain code and schematic etc.
have several hard drives around.
can it be converted to use a 18f1320??
ETO member Alwindawee made what I think is a clever POV.
He started with the motor from a hair blow dryer.
The clever bit is that he used the motors brushes to route power to the POV circuit.
He removed the bearing from one end and cut the endwall of the motor away. He used a larger bearing with an inside ID larger then the motor shart. A bushing to fit the ID was glued to the motor shaft. Two holes drilled in the bushing allowed him to run wires from the motor armature to the POV..
There are pictures somewhere. Perhaps birdman still has them.
Note: Blow dryers are line voltage. Some/all use the heating element to drop the voltage to a few volts. That and a bridge rectifier provide the DC for the low voltage motor.
The one I pulled apart has a nice looking ducted fan attached to the motor. Had me thinking hovercraft.