Force Sensitive Resistor
This Force-Sensing Resistor (FSR) has an active area of Ø12.7mm and a thickness of just 0.46mm. Overall length is 30.5mm and the device has a actuating travel of 0.15mm. The FSR is a robust, Polymer Thick Film (PFT) sensor whose material exhibits a resistance change when a force or pressure is applied. The sensitivity and performance of the FSR is optimised for use in human touch control applications such as automotive electronics, medical electronics and industrial PCs.
Simple and easy to integrate
Actuation force as low as 0.2N
Sensitivity range to 20N
Robust, up to 10 million actuations
When external force is applied to the sensor, the resistive element is deformed against the substrate. Air from the spacer opening is pushed through the air vent in the tail, and the conductive material on the substrate comes into contact with parts of the active area. The more of the active area that touches the conductive element, the lower the resistance. All FSRs exhibit a “switchlike response”, meaning some amount of force is necessary to break the sensor's resistance at rest (approximately 1 MO), and push it into the measurement range (beginning at approximately 100 KO)
Operationally, an FSR is very similar to a strain gauge, the main difference being that a strain gauge's backing deforms with the resistive element, while an FSR's does not. This fact is important to consider when mounting an FSR against a support, as discussed below.
The same applied force will result in a wider output swing in a FSR than a strain gauge. Strain gauges, however, have higher accuracy than an FSR. Depending upon the particular needs of the application, one may choose one or the other. Ultimately, a major consideration in the choice of a sensor is cost; a major advantage of FSRs is their low cost.