Is there a machine guard sensor for the detection of human contact?

[Gavtech]

A client of mine has informed me of a sensor for safety applications which has got my head scratching.

The application, he assures me, was on the guard of a docking/chop/mitre saw, which retracted the blade in the presence of human flesh. This was demonstrated by using a sausage and trying to perform a cut! Very little damage occurred to the sausage.

Does such a sensor exist? If so what principle does it work on?

 

[IRstuff]

For bare flesh, maybe, since you could potentially sense the warmth above ambient, using an IR thermometer.

Other possibility might be small electrical current to a floor pad?

Better yet, a large enough voltage to shock the person away?