A Force-sensing Resistor (FSR) is a special type of resistive sensor that can detect physical pressure, strain, and weight. They are often used in interactive projects to detect when a user is touching components. The Pololu 1.5” square FSR is an interactive sensing device that has a square active area of 1.5” on a side. The sensor's resistance increases when a stronger force is applied to its active area. It also has a wide range of response rates, from 100 to 10,000 ohms, allowing for sensitive sensing. The FSR has a robust flex sensor built-in for long-lasting durability and can be used in a variety of robotic and electronic applications.