So I started building my Spirograph today with 3 PC fans (I plan on swapping the 3rd one for a motor which I can use a reverse switch on some time in the future).
However this is something I don't fully understand with the mirrors.
the first 2 mirrors me and my dad tried to get completely centered (and completely flat). Getting it flat was no problem, but when we turned it on you could see that it wasnt completely centered. Then the 3rd mirror we actually managed to get completely centered.
When i shined my laser at one of the fans with a slightly off centered mirror the image produced was a strait line.
When i shined my laser at the fan with the completely centered mirror the image produced was the exact dot (as if I was just pointing it at any old mirror).
So one thing i was never able to understand, am I supposed to have all the mirrors slightly off center?
another possibility is having the mirror itself glued on at a very slight angle, (this is what multiple people have done from what I've heard. Having it at a small angle should make the dot become a circle) however Niko told me it should be glued on flat, no angle.
I will work on it some more tomorrow, but right now I'm just a bit confused with getting the mirror on correctly.
Another thing i tried was positioning all 3 fans next to eachother and turning them on, I got a thin circular shape that seemed to be turning inside out. The third fan is the one with the centered mirror, so I unplugged only the 3rd fan and the shape was the same. It's obvious the 3rd mirror needs to be a bit off centered. But while I'm at it, should I put each mirror at a very slight angle?
keep in mind the image below is using ONLY ONE MIRROR.
ok so this answered my question. he says you want it to be as centered as possible, and he stuck a thick piece of paper under the mirror to raise it up about 2-3 degrees.
Maybe Niko's mirror was at a slight angle that couldnt easily be seen. http://www.instructables.com/id/SQ9UJMEFCZERCF3/