SparkFun: SoftPot Variable Potentiometer
The softpot is a thin potentiometer that can be used by just touching along the strip. The following is an excerpt from the SparkFun web site: These are very thin variable potentiometers. By pressing on various positions along the strip, you vary the resistance.
Inputs and Outputs
The potentiometer has a variable resistance between 100 and 10,000 Ohms that changes linearly with location pressed. When either pin 1 or 3 is connected to ground and the other is connected to VCC the location of the touch can be calculated by reading the voltage on pin 2.
Hook up pin 1 on the SoftPot to GNDA_ADC (pin 34) and pin 3 on the SoftPot to VDD_ADC(1.8V) (pin 32). Pin 2 on the SoftPot can be connected to any remaining AIN channels. This voltage can then be read as any normal analog in reading.