Hi all,
I'm working on building a 3-D Zoetrope. I have the turn table/ motor/ and a enclosure built already. The turn table is geared to rotate at 59-62 RPM. Now I need to sync the turn table to a Strobe light or LED array that will fire 16 time per second/ per rotation of the turntable. The rate of fire must be specifically timed to the 16 sculptures mounted on the turn table. We have tried a magnetic sensor but the magnetic fields have proven problematic as you cannot adjust to the variations in the fields from magnet to magnet. I have thought of using an motor encoder or a optical sensor to trigger the LED or Strobe and that is when I came across the Arduino web site. Has any one completed a device like this before? Any help would be appreciated.

I made a mechanical form of 3D glasses from two motors and a shutter disc in the early 90s.
I synchronised the motors to the frame rate of the TV display with a circuit called a phase locked loop.

I think you could do it using 16 small magnets attached to the periphery of the turntable, and one Hall sensor that senses the passing of each magnet. The Hall sensor is a digital device, so variations in the strengths of the magnets have little effect. Alternatively, use fewer magnets and a phase locked loop as Mike mentioned. You can implement a digital phase locked loop using an Arduino.