Continuous Rotation

twilight · February 23, 2009, 5:35pm

Can anyone tell me how to set the endpoints or limit the rotation on a hi tek HSR1422CR Continuous rotation servo. I would like to limit the rotation to 270 or 360 degrees, to prevent the wires from being entangled turing a panning operation on a pan/tilt camera assembly. Thanks

twilight · February 23, 2009, 11:08pm

By the way, I am controlling the servo using a Futaba radio transmitter.
Thanks
Chris

robotdude · February 24, 2009, 2:24pm

Servos modified for cont. rotation can not be commanded to a position. You can only control the speed and direction of rotation. If you require +270Ã‚Â° rotation then you should add a 1:2 gear to the output. Note, this will reduce the resolution by half.

twilight · February 24, 2009, 3:25pm

Thanks,
What if I only wanted 180 degrees, can I get that from,
a standard sized servo without any additional gearing, How?
CR

twilight · February 24, 2009, 3:30pm

Where do I get these 1:2 gears?
Are they internal?
CR

robotdude · February 24, 2009, 3:52pm

The servo can do 180Ã‚Â° but the futaba radio makes pulses that will only move the servo about 90Ã‚Â°.

I don’t have a source for the gears. They would be added to the output of the final gear.

zoomkat · February 24, 2009, 11:35pm

The below pages may have a couple of ideas. The first page has some info on using limit switches and diodes to make a reversing motor setup. The bottom page is a blind setup where the 180 deg rotation servo turns a blind shaft ~2 turns.

geocities.com/zoomkat/switch.htm
geocities.com/zoomkat/blindtilt.htm

bigbug-2 · March 1, 2009, 1:39am

The by far simplest method would be to buy a servo designed for that application. That beig said, you could simply do it in code. Let the servo travel x over time then change direction and travel x over time.

zenta · March 1, 2009, 4:26pm

That can be solved by using a servo stretcher.

twilight · March 1, 2009, 4:49pm

Thanks
I like the servo stretcher and its affordable
CR