The other day DJ suggested an easy way to make a touch sensor, see this thread
So I started playing with that idea and made a couple of touch sensors by soldering a piece of foiling tape (I "borrowed" some from my wife's stain glass supplies) to the end of a wire. I attached the wire to an ADC Port and put the foiled end on the robot. Wrote a script and it works pretty good.
Here's a picture of the sensor.
A short video of them working.
Thanks for the idea DJ !