'amplify' movement using hobby servo and Prop-1?

[electricbob]

Hello... I want to move an object back and forth along a "track" that spans about 15 feet. When triggered, I want the object to be able to stop and "jump over to" any point along this "track".

All I have is a Prop-1, and hobby servos, and I am not sure about how to go about this:

Is there a way to use the 90 degree span of a servo's movement to 'amplify' or even to 'represent' the full 15-foot span of this track?
Is there a way to use continuous-rotation servo and gear assembly to drive the object along the track?
I want to be able to mimick the movements of a small servo and somehow transfer those signals to drive greater distances and greater strength or torque... ?... ...anyhow your comments would be appreciated.

[clinefx1]

You may want to start looking at servo amps.  Basically motor drivers with a feedback system.  RoboteQ has a few that may work for you and they can translate a servo pulse into a liner location.  For feed back I'd research string pots.  For driving things you may have graduated to the wheelchair motor club with chain or belt drives.  Then again it's always easier to find something that already exists and modify it for your application. 

Good Luck
-Chris

[menehune]

How big/heavy is the object?  A few ounces?
Can you mount the servo 15 feet below the track and use a long arm to get the exaggerated movement?  This would be similar to an analog meter movement with a directly driven needle.

[electricbob]

Actually this is going to be a pair of "eyes" that pace back and forth in a closed garage (with windows). When someone approaches and triggers a sensor , the "eyes" suddenly stop and rush over to a particular place on the "track". The eyes assembly will probably be a couple of pounds.

[JonnyMac]

You might consider a Parallax HB-24 motor controller and a clothesline type setup.  A friend, Steve, did this with a flying bat in his haunt and it worked quite well.  The Prop-1 sensed a "victim" and caused the bat (with LED eyes) to fly down the hall to the guest; when the guest passed the bat would back up to the starting position.  As I remember the was a trigger input, two limit switch inputs, the HB-25 (servo pulse) output and the LEDs.