How does a force sensing resistor work?

 A force sensing resistor (FSR) is a resistor whose resistance varies in reaction to applied force or pressure. It is typically made up of a sensing material (such as conductive polymer) embedded in a flexible substrate with electrical connections on each side. When force is applied to the surface of the FSR, the sensing material compresses or deforms, altering its electrical resistance.

The mechanism behind the operation of an FSR can vary depending on its design, but generally, it works based on the principle of contact resistance. When no force is applied, the sensing material is in a relaxed state, and its resistance is relatively high. As force is applied, the material compresses, bringing the conductive particles closer together or increasing the density of conducting pathways, which lowers the resistance.

The relationship between force and resistance in an FSR is not linear; instead, it's typically logarithmic or exponential. This means that small changes in force can cause significant changes in resistance, especially at lower force levels.

FSRs are widely employed as pressure sensors in a variety of applications, including touch-sensitive interfaces, robotic grippers, medical devices, and musical instruments. They provide benefits like as low cost, versatility, and ease of integration into electrical circuits. Furthermore, their analog output is easily interfaced with microcontrollers such as Arduino to enable a variety of sensing and control applications.

What is the function of FSR?

A force sensing resistor (FSR) detects and measures the force or pressure applied to its surface. It accomplishes this by adjusting its electrical resistance in reaction to applied force. FSRs are designed to be sensitive to even small levels of force, making them useful in a variety of applications requiring force or pressure sensing.

Some common functions and applications of FSRs include:

Touch Sensing: FSRs can be used to detect touch or contact with surfaces. They are commonly found in touch-sensitive devices, such as touchscreens, interactive displays, and capacitive touchpads.

Human Interface Devices (HID): FSRs are used in various human-machine interface applications, including buttons, switches, and pressure-sensitive input devices like musical keyboards, game controllers, and stylus pens.

Pressure Sensing: FSRs are utilized to measure pressure in medical devices, such as pressure-sensitive mats for patient monitoring, prosthetic limbs, and rehabilitation equipment.

Robotics: FSRs are integrated into robotic grippers and manipulators to provide feedback on the amount of force exerted during grasping or handling tasks. This allows robots to adjust their grip strength and prevent damage to delicate objects.

Safety and Security: FSRs can be employed in security systems, smart textiles, and automotive applications to detect intrusions, occupancy, or changes in pressure, enabling the implementation of safety measures or alarm systems.

Biomechanics and Sports Equipment: FSRs are used in biomechanical research and sports equipment to measure forces exerted during activities like running, walking, or weightlifting. They can help optimize performance, prevent injuries, and design better-fitting equipment.

Industrial Automation: FSRs are used in industrial automation to monitor and manage activities that require force or pressure, such as material handling, assembly, and quality control.