would this work through 60mm of cured concrete ?
I make concreto countertops with embedded clocks
  and I would like to embed sensors in them.

See a not-very-good uTube video.
http://www.youtube.com/v/dNsjyZ4yAHc


On Feb 17, 2008, at 4:39 PM, Jinx wrote:

> It's possible to detect a hand or any other conductive object
> at a distance of 6" by using capacitive sensing

Scott, the attached circuit will do just that. Sensitivity is mostly
dependant on the size of the metal plate. I've embedded these
behind walls as secret switches, using 100mm x 100mm of
adhesive aluminium foil as the sensor. A sensor that size will
react to a hand (parallel is best at that distance) through 100mm
of averagely-dry wood. Although I've described it as "touch" it's
actually a proximity detector. 
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