Force Sensitive Resistors

A force sensitive resistor (FSR), also known as a force sensing resistor or piezoresistive force sensor, uses layered materials that change resistance when force is applied directly to its surface. Unlike strain gauges, which measure substrate strain via resistance changes, FSRs detect force on the sensor itself, not substrate deformation. 

Thanks to their low costs and durability, FSRs are commonly used in medical devices to measure localized pressure (e.g., in prosthetics), in wearable systems to assess gait stability or footfall asymmetry, and in retail applications like smart shelves or point-of-sale systems to detect object placement or pressure.