
Loscha:
"These are a series of USB interfacing modules that connect electronics in the real world to the virtual world of your computer. To me, they seem reasonably priced, and the support and documentation seems well organized.
Some examples are present for MAX/MSP, and a library of interfacing code for the majority of flavours of coding that people use (although ChucK isn't here, I'm sure if enough people notice these exist, it's a possibility!)."
The PhidgetCircularTouch pictured
"The PhidgetCircularTouch detects changes in the capacitance between the on-board electrodes and the object making contact. The side of the circuit board opposite the connector and components is the side intended for contact." You can find more info here