POV project

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1

I'm currently working on a POV project similar to the strobeshnik HDD clock. Strobeshnik HDD Clock

I need to strobe the LED's at the right time to produce the correct POV effect, to do this I need to know where the disc is at all times. As I am driving the motor (BLDC) with a sensorless RC ESC this data is not directly available to me.

My initial thoughts were to use two encoders, one for a home index (1 pulse/revolution) and another to semi-accurately determine where the disc is in relation to the home index (maybe 32 pulse/revolution?).
This method would allow me to (hopefully) accurately strobe an LED at the correct time. I am however reluctant to try this approach as it would require the use of two SMD optical reflective encoders and a custom PCB to mount them on. I am also slightly concerned with the amount of interrupts that would be generated from this. The disc could be spinning anywhere from 2000 - 7000 rpm generating up to ~3800 interrupts/sec. Can the arduino realistically handle this and the strobing of the LED's?

My next thought was to just have one encoder with a single index position and then attempt to use timers to strobe the LED at the right time. I'm not really sure if this would even work.

If anyone has any better ideas or input towards my current ideas then I would very much appreciate it. :slight_smile:

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My next thought was to just have one encoder with a single index position and then attempt to use timers to strobe the LED at the right time. I'm not really sure if this would even work.

Sure it would. Just having a single index pulse (perhaps from a optical gate or magnetic pick-up could start your timing cycle, after that its just working out delays needed to display the number of characters for your POV. That is how the first POV displays I saw working in the late 70s using the first micros. Most everything can be done in software with just a hardware index pulse.

Lefty

3

That doesn't sound so bad then, thanks for the advice :).
Having the LED's strobe as the characters pass over them would appear to be more timing sensitive than a traditional spinning LED display... Do you think timing could still work for this type of display?