Single Servo Motor drive

[Toolmaker]

Hi ! I am new at this so please bear with me
I am looking to drive a single servo motor. What i need to do is rotate a circle every 12 inches (circumference) all i need to do is hook up a single button, when pushed it rotates the circle 12 inches then stops, push again and it repeats the process. One direction only.
If you can assist me with the most simple way to achieve this, it would be appreciated. Even if there is a way to do this without the use of a servo motor. I chose a servo motor because of the strength, it needs to be high horsepower for the application, more or less a feeder system.
Thank you!

[RotarySMP]

What are the specs of the motor Does it have an encoder, or a tacho? Brush type, under 80V 20A with an encoder? If so you could use a gecko G320 to drive it. If you are or have access to someone with a bit of a bent for electronics, it shouldn't be hard to make a up a little circuit which outputs X step pulses each time a button is pushed.

Then you just need to make up a simple DC power supply, for which there are instructions on the Geckdrive.com site.

You could scrounge an old pentium 1 computor, install free dos, and use turboCNC with a very simple program to command the gecko if you don't want to make a dedicated circuit.
G91
G00 C12
M04

That will cost nothing if you are a good scrounger, but take up more space.

[Bloy2004]

What precision are you trying to achieve. You could do this with a multi-pole relay and switchs combined with a "ratchet" sytem. push button to energize the relay, the motor moves the circle, a cam trips a switch that stops the motor and indexes the circle at the correct location.

..a simplified overview....

[DennisCNC]

^^ Simple and reliable!

[H500]

You did not say how fast it needs to turn, or how much torque it needs.

A servo motor actually does not have that much torque at low speeds. It's main advantage is the ability to run at high speeds. A stepper would be better.

[Evodyne]

Most feeders (auger type?) rotate rather slowly. If you reduce the speed of even a small motor enough you'll have a great deal of torque. An 12 VDC electric window opener assembly from a car has both a powerfull motor and a good deal of speed reduction/torque multiplication via a pinion/spur gear. You could reduce the speed further with chain and sprockets or pulleys and belts if needed.

Follow Bloy2004's suggestion of a latching relay reset by a switch. You can glue a magnet to the feeder and use a reed switch to unlatch the relay and stop the indexing. Very simple and rugged.

Evodyne

[Toolmaker]

Thank you everybody for your suggestions
I now have some great ideas for what i need to do.
After this project is complete, i am planning a home cnc machine build.
I will be definitely looking for your help again!