What is a Force Sensing Resistor?

A force sensing resistor (FSR) is a variable resistor, constructed of several thin flexible layers, that vary in resistance as pressure is applied and released. As pressure is applied, the resistance lowers and then returns to its original value as the pressure is removed. An FSR’s main purpose is to measure the force applied to a specific area and then relay that information via selected output electronics.

All FSRs use high-resistance, carbon-based inks which, along with other design factors, can be re-formulated to alter the functionality. FSRs are available in several options including single-zone, discrete array, and matrix array constructions. FSRs are commonly used in Industrial Automation, Healthcare, Transportation, and Wearable applications.

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Force Sensing Capabilities and Applications

Force sensing resistors can sense forces as large as a human body or as light as a vial of medicine.

What Can a Force Sensing Resistor Detect?

  • How quickly an applied 
    force changes
  • How much an applied 
    force changes
  • Whether something has been touched 
    or come into contact with something
  • Whether a force has exceeded 
    a predetermined threshold

Examples of FSR Applications

  • Up/Down and Force/Speed Controls
  • Musical Instrument Controllers
  • Infusion Pumps
  • Podiatry Foot Gate Analysis
  • Motor / Tool Speed Control
  • Robotic Finger Tips
  • Seat / Bed Occupancy Detection
  • Inventory Control
  • POS Displays
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Force Sensor Configurations

Shuntmode_Image

ShuntMode

Capable of detecting a wider range of forces with a more linear output.

  • Consist of printed silver interdigitated fingers that are shorted (“shunted”) by a printed FSR carbon layer.
  • Can detect a wider range of forces with a more linear output.
  • Are generally less costly due to fewer print steps and reduced ink usage.
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ThruMode

More receptive to lighter forces, but can saturate more quickly.

  • Are more receptive to lighter forces
  • Not limited to the same print constraints as the ShuntMode’s interdigitated silver fingers, 
    thus allowing for smaller form factors
  • Require more silver and carbon ink, thus making them more costly than the ShuntMode FSR.

Designing and don’t know where to start?

Check out our design guide. A powerful tool for beginners and seasoned veterans.

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Types of Force Sensors

  • Single-zone

    One sensing location with 2 leads (traces).

  • Matrix Array

    Multiple sensing locations connected to rows and columns. (ThruMode only)

  • Discrete Array

    Multiple sensing locations each with its own trace and single or multiple
    common traces. (ShuntMode only)

  • Linear Potentiometers

    Sense force on a single axis, along with the force applied (a force sensing slider).

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Where to start

With all the different customization options and use cases, it might seem overwhelming.

Contact our expert team today and take the pressure off yourself.