While looking for a perimeter alarm I found this -

Seal devices against all possible contamination
Detect switch 'pressing' through 50mm of panel (32 switches per sensor chip)
Measure all sorts of fluid levels
Detect approach to and crossing of boundaries
Directly operate via logic output, or
Communicate via uart (slow) or SPI (@ 5Mbit)
etc, etc, etc starting at US$6.00 in single quantities (110 series)

More elaborate models allow user programing of electrode charge time,
electrode dwell, detector transfer and inter-reading gap times.  Re-set and
recalibration, etc can be performed under uP control or left to the chip
itself to perform when it deems it necessary.

http://www.qprox.com/background/applications.shtml

Be sure to download the FAQ, White Paper and the Product Summary Guide.


WOW !

Bye.

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