A Force-Sensing Resistor (FSR) is a type of resistor whose resistance changes when a force is applied to it. In Pololu’s 0.2" FSRs, the resistance is approximately 300O when no force is being applied and decreases as the force increases. The decrease in resistance happens pretty quickly up to about 18.6 kg of force, and then levels off, making it ideal for sensing the light touches of a human finger or lightweight objects. FSRs can be used to detect changes in force and can be used in a wide variety of applications, such as pressure detection, load cell production, and threshold detection.