Bournes has a series of Linear position sensors (POTS)
     Model Series 400.  They look a little pricy in the picture.

     You could use a linear volume control off of an old style stereo.

     Also there's linear ratiometric transformers, and linear optical encoders.

     We considered making our own optical encoder assembly at my last job. We
     were trying to use a HP 9700 series slotted encoder module, and some Gerber
     files of lines that we had our PWB shop plot on film for us.  We got good
     results in the lab, but could not convince ourselves that we could move it
     to production.

     Joe

     -----------
     ello

     I need a very accurate linear position sensor, that can measure verticle
     object travel of approx 1.5 inches. Cost is an issue. It will be an input
     for a PIC16F84, so a digital signal would be less work.

     Can anyone help?

     Thank you

     Jon Petty