Fruit machine (slot machine)

[wombleboy]

I'm half way through my MAME cabinet, and starting to think about my next project. A fruit/slot machine is on my mind at the moment, but I can't figure out how to control the reels. With a servo it's easy to control the degree of rotation (so the electronics can control which symbol the reel lands on), but these generally only move through +/- 180 degrees. With a modified continuous rotation servo, you lose the ability to control the number of degrees it rotates through. Any thoughts on how to get round this? Perhaps a stepper motor (not something I've looked into before) ?

[ed12]

look up the bally
1 arm bandits
3300 or 5000
u will get the idea

ed

[RandyT]

You will need an absolute encoder, or an incremental encoder with an external indexing means, for each wheel.  You could probably get away with just one for all three wheels, with mechanical clutches and brakes for each wheel, so long as you could re-synchronize their positions when they start spinning again.