"Pulsed" 3 Motor Spyrograph

[Rhith]

Last night I was all too restless and I really wanted something to do. So, I decided to take three of my cheap computer fans, glue some mirrors onto them and turn it into a little spyrograph. I got it all done and since these fans and the power supply are both old it seems to "pulse" power to them in slight variations that causes the reflected pattern to morph and change. Since what it is doing is a bit hard to explain I just took a video of it that's a bit over a minute long.






Just so it's clear, I did NOT set up anythign to cause it to do this.

 

[Cyparagon]

It looks more like one of the fans is turning just a bit faster than the others due to minor differences in the coiling or something. That would also create this effect.

 

[Rhith]

But would it constantly change randomly like that? My guess was that one of the fans was "pulsing" and changing speeds so that is the probably cause of things. I guess I should just test each individually and see what kind of "circle" they give.

 

[darklandz]

yeh y do some mirrors make a perfectly round circle, some make like an oval type circle and some dont even make circles, instead make wierd type patterns?

 

[Cyparagon]

the pattern doesn't look random. It repeats itself. The circle from any one fan will look identical since your eye can't tell if it's spinning at 10Hz or 11Hz, but the difference becomes noticeable when a second "dimension" is added.

 

[Rhith]

Also an oval off of one mirror would be from holding the beam at an angle so that it would cause it to have an elongated part that reflects off of the surface.