Force Sensitive Resistors
Prototype force sensitive resistors for printed electronics
Force Sensitive Resistors
Prototype force sensitive resistors for printed electronics
A force sensitive resistor (FSR), also known as a force sensing resistor or piezoresistive force sensor, uses layered materials that change resistance when force is applied directly to its surface. Unlike strain gauges, which measure substrate strain via resistance changes, FSRs detect force on the sensor itself, not substrate deformation.
Thanks to their low costs and durability, FSRs are commonly used in medical devices to measure localized pressure (e.g., in prosthetics), in wearable systems to assess gait stability or footfall asymmetry, and in retail applications like smart shelves or point-of-sale systems to detect object placement or pressure.
APPLICABLE INDUSTRIES
- Consumer electronics
- Healthcare
- Retail
- Smart textiles
- Automotive
- Sensors
- Aerospace
COMMON MATERIALS
COMMON SUBSTRATES
- Polyethylene terephthalate (PET)
- Polyimide
- Polyvinylidene fluoride (PVDF)
- FR4
INDUSTRY
INDUSTRY
FUTURE OUTLOOK
FAST FACTS
Frequently asked questions
FSRs typically have a sandwich structure, consisting of:
- Two substrate layers, usually made of flexible polymer films like PET or polyimide
- Conductive electrode patterns printed or deposited onto the substrates (e.g., using silver ink)
- A layer of the piezoresistive conductive polymer composite material, applied as an ink or film
- A spacer layer, often an adhesive gasket, which separates the active layers in the unloaded state and creates an air gap
While both force sensitive resistors and strain gauges respond to force, FSRs measure the force applied directly to the sensor's surface. In contrast, strain gauges are designed to measure the strain (deformation) induced in a substrate or structural element to which they are bonded; this strain is then indirectly correlated to the force causing the deformation.
FSRs operate based on the principle of piezoresistivity, where the electrical resistance of the sensor material changes when subjected to mechanical stress directly on its active surface. Typically, this manifests as a decrease in resistance corresponding to an increase in applied force, transitioning from a high resistance state (often in the mΩ range) when unloaded to a lower resistance state (kΩ range) under load.
FSRs typically have a sandwich structure, consisting of:
- Two substrate layers, usually made of flexible polymer films like PET or polyimide
- Conductive electrode patterns printed or deposited onto the substrates (e.g., using silver ink)
- A layer of the piezoresistive conductive polymer composite material, applied as an ink or film
- A spacer layer, often an adhesive gasket, which separates the active layers in the unloaded state and creates an air gap
FSRs operate based on the principle of piezoresistivity, where the electrical resistance of the sensor material changes when subjected to mechanical stress directly on its active surface. Typically, this manifests as a decrease in resistance corresponding to an increase in applied force, transitioning from a high resistance state (often in the mΩ range) when unloaded to a lower resistance state (kΩ range) under load.
While both force sensitive resistors and strain gauges respond to force, FSRs measure the force applied directly to the sensor's surface. In contrast, strain gauges are designed to measure the strain (deformation) induced in a substrate or structural element to which they are bonded; this strain is then indirectly correlated to the force causing the deformation.