Force Sensing Resistors (FSR) find applications in various fields where sensing and measuring force or pressure is essential. They are commonly used in human-machine interfaces, such as in touch-sensitive devices where they sense the pressure applied by a user’s touch. For example, FSRs can be integrated into touchscreens, trackpads, and interactive surfaces to provide tactile feedback and control functions based on different pressure levels. In robotics, FSRs are used to measure grasp force or interaction force between robotic limbs and objects, improving precision and control in robotic applications.
A force sensor, such as an FSR, can be used for a wide range of applications that require accurate and reliable force measurement. In sports equipment, force sensors are integrated into equipment like golf clubs and tennis rackets to analyze the force exerted during play and provide feedback to improve performance. In medical devices, force sensors are used in prosthetics to detect the pressure applied by the user and adjust the device’s response accordingly. They are also used in rehabilitation equipment to track patient progress and ensure safe effort levels during therapy sessions.
A basic force sensing resistor (FSR) consists of a polymer-thick thick film sensor (PTF) that changes resistance when pressure or force is applied to its surface. Inside the FSR there are conductive particles embedded in a polymer matrix. When force is applied to the sensor surface, the conductive particles move closer together, increasing the number of conductive paths and reducing the overall resistance of the sensor. This change in resistance is proportional to the force applied, allowing the FSR to provide a linear response to different pressure levels. The simplicity and effectiveness of FSRs make them widely used for tactile sensing and force measurement tasks.
The operation of a force sensing resistor (FSR) relies on changes in its electrical resistance when pressure or force is applied. Inside the FSR, a resistive material with embedded conductive particles is sandwiched between two conductive layers. When force is exerted on the surface of the sensor, the distance between the conductive particles decreases, creating more conductive pathways and thereby reducing the overall resistance of the sensor. This change in resistance can be measured using simple electronic circuits, such as voltage divider circuits, to quantify the amount of force applied. FSRs are designed to provide an output signal proportional to the force exerted, making them suitable for various applications requiring precise force measurement and tactile sensing capabilities.