PoV & visual perception speeds

[Ugi]

Hi Guys
I wanted to ask you a briefly about this project: http://www.evilmadscientist.com/2008/a-simple-persistence-of-vision-approach-to-lissajous-figures/
Comments are closed on the blog post so I came here.

I’m trying to design an easy PoV project for some kids I do a science club with.  The electronic side is easy enough, but my question is about the physical movement of it:  You show some great figures in the post above.  Do you remember whether they were visible with the naked eye or are they only revealed in a long-exposure photograph?  If visible, what sort of rate was the pendulum?  I guess only 1-2 Hz at most.

I’m wondering whether I need to move my PoV device through a whole display cycle in less than 1/25th second (which seems to be the “frame rate” of the human eye) or whether a slower rate will do.

Any thoughts appreciated.

Thanks

Ugi

[Windell Oskay]

Yes, these were 1-2 Hz kind of motion.  It’s visible to the eye if your gaze is fixed– but (like with most POV devices) you won’t see it if you follow the electronics with your eyes.  If you make a shorter pendulum (so that it will have a shorter period), you might want to turn up the oscillation frequency.

[Ugi]

Thanks Windell – I must try the idea of looking at something fixed nearby to make them easier to read by eye.

Cheers

Ugi

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