> Well, I was not directly involved in choosing this part but at this
> point it is one of several being tried, of different technologies.
> This is not actually going to be used to sense a human finger but
> rather contact by cardboard boxes and other items in an automation
> system, and he doesn't really care too much about the ability to tell
> where (along the length) it was bumped, only whether contact was made
> or not. This part is nice because it is sealed, cheap, rugged, and
> very long (about 50cm) - the contact area he needs to sense is long
> and not a point.
>=20
> Sean

OK, so it sounds rather like he really needs a large button shaped to suit =
the touch area. I would still think in terms of trying a capacitive touch s=
ensor, using a metalized Mylar film as the 'button' element, and measuring =
the capacitance change from the rest position. With the film at a suitable =
distance above the PC electrode any bump would change the capacitance enoug=
h to sense. Maybe use the capacitance as the capacitor in an oscillator and=
 sense the frequency change.
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