Once, years ago, I read an article that described a rather neat (in my mind, at least) touch sensor design. It was a ring that was mounted around the middle of a robot; the ring was made in such a way that when a contact was made with it, the software could calculate where on the ring the touch occurred. This was not done with multiple touch switches; it relied, instead, on the electrical characteristics of the materials that the ring was made from. I thought it was a capacitance based system.
However, I am unable to find the article and I am unable to find any references to such a sensor. Maybe I dreamed it :-) Weirder things have happened. But, I figured there's always a chance that someone on this forum has some idea of what I am talking about.
To recap---imagine a ring of some sort of material. A current is running through it being measured by the software. When something presses against the ring at a certain point, the resistance/capacitance/something changes which can then be used to determine where on the ring the contact occurred. So, you get a 360 degree bump sensor.
any help? anyone?