Bump sensor with variable resistance

OK, many months ago, I ran across a clever design for a robotic bump sensor. It used a flexible rod, bent into almost a complete circle around the robotic chasis. The
rod was constructed so that when pressed anywhere along it, the resistance being seen by the system would change in a way that would allow it to calculate where the touch took place. So, rather than use 16 touch sensors, or some other number, you ended up with the ability to tell where contact occurred anywhere on the ring.
Sigh. I cannot remember the details, though, and I cannot find the article. Heck, I cannot even remember if it was online or in Servo/Nuts&Volts/Robot/something else.
I am hoping this brief description jogs someone's memory enough to give me a pointer. Any thoughts?
Thanks, kenny
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Because of the Sporge attack (am I spelling that right?) which essentially shut down this newsgroup, Gordon McComb set up a replacement forum on his web site. That is the place to post your message.
http://robotpalace.com/forum /
Joe Dunfee

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