Position sensor recommendations?

[pcar]

What is the most efficient or most cost effective method of setting up sensors to monitor 5-6 positions of a shaft (about 1.5" OD) that rotates and moves linearly. The movement is only 1/2" or so in any direction. This is for a production run rather than a one-off.

I'm thinking multiple magnetic sensors, but are there more compact methods? I'm trying to reduce the number of brackets required to hold mag sensors and magnets in place. BTW, sensor-to-sensor distance might be variable from one install to another.

thanks,
pcar

 

[Warpspeed]

Probably not more compact.

Because it both turns and slides it most probably must be a fully non contact method of sensing to prevent mechanical jamming. Reflective optical is going to be much less convenient than magnetic.

Is pneumatic a possibility? An airline and some slots, grooves, or holes ?

 

[Ron07663]

Hall-Effect gear tooth sensors can sense shaft position similar to Crankshaft position sensors used on many engines. You would need to mount a 5 or 6 tooth ferrous "gear" on the shaft. The location of the tooth would correspond to the desired sensed position. If the gear were wide enough, the linear movement of the shaft would not be a problem.
The output of the sensor can be feed to a simple circuit to output 1 of 5 (or 6) signals. If the shaft can rotate in both directions you would need a sensor that has a direction sensing capability.