Initial report by Chang Soo Lee 11/27/05
Force Sensor Resistor is great way for measuring pressure and force which is from Interlink Electronics.
Application
The FSR can be applied to various fields such as industry, medical science, robotics, and body pressure equipment.
- Industrial Application : Nip Roller, Robotic Grip Forces, Packaging Seals - See detail
- Medical Application : Insulin Pump, Surgical Instruments, Neck/Back/Knee-Brace Fit - See detail
- Dental Occlusal Analysis System - See detail
- Recreation / Entertainment Application : Training devices, Toys & Electronic Games - See detail
- Automotive Application : Automotive Crash Tests, Brake Pad, Airbag Force - See detail
- Building Tap-Tile for dance or installation applications
- Building virtual percussion instrument controllers
- And more...
Electrical Characteristics
Datasheet Download
| Parameter | Value |
| Size Range | Max : 20" x 24" / Min : 0.2" x 0.2" |
| Device Thickness | 0.008h x 0.050h |
| Force Sensitivity Range | < 100g to > 10kg |
| Pressure Sensitivity Range | < 1.5psi to > 150psi |
| Part-to-Part Force Repeatability | +-15% to +-25% of established nominal resistance |
| Single Part Force Repeatable | +-2% to +-5% of established nominal resistance |
| Force Resolution | Better than 0.5% full scale |
| Break Force | 20g to 100g |
| Stand-Off Resistance | > 1M |
| Switch Characteristic | Essentially zero travel |
| Device Rise Time | 1-2 msec |
| Lifetime | > 10 million actuation |
| Temperature Range | -30 degree Celsius to +70 degree Celsius |
| Maximum Current | 1mA/cm2 of applied force |
| Maximum Voltage | 5V |
| Sensitivity to Noise | Passive device |
How it works
Force Sensor Resistor displays a decrease in resistance with an increase in the force applied to the active surface.
FSR is composed of 3 portions ( Interlink Electronics Model No. 402 ).
- Vent : The vent assures pressure equilibrium.
- Spacer : The width of gap and fingers of the conductive grid.
- Active Area : The area responds to force with decrease in resistance.
- Tail : The area where the busing system terminates.
Microcontroller Connections & Pin Descriptions
There are two pins for a FSRs electrical access at the end of tail. Connect one pin to power (5V) and the other pin to Microcontroller.
Code Sample
Serial Communication for Microcontroller - Analog Input
Serial Communication for Microcontroller - Digital Input
Serial Communication for Processing
Typical Behavior
Force vs. Resistance
This test is from Interlink Electronics for force-resistance characteristic being response of evaluation model #402. The graph is exhibited typical response behavior of FSR. Increasing force and then decreasing resistance.
I tested force and resistance characteristic with 10ohm, 1Kohm and 100Kohm resistors. First, I put from low number of resistor (10ohm) to high number of resistor (100Kohm). If I used 10ohm, a decrease in resistance was slow and needed more force. On the contrary, If I used 100Kohm, a decrease in resistance was fast and required less force.
Application Notes
DDR Game Pad Hacking - Digital Input
Xport & TapTile - Networking
FSR - Single Analog Input
FSRs - Multi Analog Inputs
