Force Sensing Resistor:
The resistor is one of the most commonly used passive components. This is generally used for reducing current flow and also lower voltage levels in circuits. There are some special purposes resistors like Force sensitive resistor, LDR, Pencil resistors etc., The FSR sensors are made of a conductive polymer which has a property of changing its resistance based on the force applied to its surface. Hence, these are termed as FSR sensors; force sensing resistor is a combination of resistor and sensor technology. The force sensing resistor is generally supplied as a polymer sheet or ink which is applied as screen printing. Both the electrically conducting and non-conducting particles are present on this sensing film. These particles are generally sub-micrometer sizes which are formulated for reducing the temperature dependence and also for improving mechanical properties, increasing surface durability.
When there is a force, pressure or mechanical stress applied to this material, there will be a change in resistance. This is made up of polymers. If force is supplied on the surface of sensing film, then the particle touches the conducting electrodes and thus the resistance of the film changes.