Or something like an ultrasonic distance sensor.

Here's one supplier:
http://www.senix.com/

DOC



At 12:04 PM 12/3/2003 -0500, you wrote:
>I know for a fact that Banner and Turk both make Inductive proximity sensors
>that can be used in harsh environments (both mechanical and electrical). Now
>the problem is that these sensors would give you a yes or no answer to the
>presence of metal very accurately but how are you going to measure distance
>from that? Fixed distance sensing is one thing but if you want to sense
>metal that can vary in distance from the sensor, you will need an analog
>output that is fairly linear in your measurement range; you might try
>talking to applications engineers at Turk, Keyence and Banner. Between them
>I am sure they will recommend a good solution albeit an expensive one.
>Madhu

http://www.robot-one.ca

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads