# Very precise way of measuring small distances?

I am looking for a somewhat cheap way of measurin small distances ( >0.1 inch) between an object and a sensor, are there any good ways to do this? I am considering the component from a flatbed scanner, but I am not sure how I would make use of this. It would be preferred to use some kind of mechanism that uses absolute positioning, so it doesn't get thrown off, but a very accurate absolute positioning method would work too. Suggestions would be appreciated.

• Contact or non contact? – Decapod Oct 11 '16 at 18:48
• How are the object and sensor mount connected? E.g. a lathe tool and a workpiece, or two jaws of a vice, or an object randomly placed in front of the sensor? How accurate does it need to be? – Andrew Morton Oct 11 '16 at 18:49
• Either define "somewhat cheap" or give us a desired resolution/accuracy. No point suggesting a £6000 capacitance sensor with 0.5nm resolution if you don't need something that good. – Jack B Oct 11 '16 at 18:50
• Get a cheap dial caliper, and hook it up (spring-loaded.)so it is always measuring your separation. This will give about 0.001 inches resolution. – WhatRoughBeast Oct 11 '16 at 19:59
• @JackB Looking for something hopefully accurate to about 1/1000th of an inch – 888 Oct 11 '16 at 22:23

Price ranges from about $25 to$500 depending on brand and performance.