In article ,
Prof Wonmug wrote:

I want to make some "spinners" with my granddaughter. These are disks
with various patterns that do interesting things when spinning. Some
change colors: yellow and blue wedges turn green, all colors turn
white. Some appear to spin backwards. Some are spirals. Benham disks
generate colors from black and white:

http://en.wikipedia.org/wiki/Benham's_top

These can be made with toothpicks like a top, but the best effects are
achieved with more controlled spin speeds. Most of them work best at
fairly low speeds (150-300 rpm).

I have an old Makita cordless drill, which works OK, but the speed is
difficult to control precisely and it's way overkill. I also have a
Dremel tool, but its slowest speed is like 2000 rpm, which is way too
fast.

Does anyone know of a simple tool, like a cordless screwdriver, that
has better speed control and goes down to 150 RPM?

Or does anyone have a better suggestion?

Is there some kind of simple turntable?

Yeah, we used to call them record players. All kinds of optical illusion
discs were made for them. Seemed to work fine at 33 1/3 to 45 RPM. On a
side note, we also made good use of album covers, thereby enhancing the
effect.


I need speeds of 150 to 1,000 rpm (I think).

How much trouble would it be to build a simple hand-cranked turntable
either gear or belt driven?