100-Pound FlexiForce Force Sensor
Measures from 0 to 100 lbs.
FlexiForce Sensor Model A201.
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FlexiForce is...
- A versatile, durable piezoresistive force sensor
that can be made in a variety of shapes and sizes
- A piezoresistive sensing device in which resistance
is inversely proportional to applied force
- A customizable, economical force measurement tool
that is easily integrated into OEM products
- A patented, ultra-thin (0.008"), flexible printed
circuit that senses contact force
- A force and load sensor that is available in three
different force ranges, suiting a variety of applications
for research and product development/testing.
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Construction
The FlexiForce A201 force sensor is an ultra-thin, flexible
printed circuit. The force sensors are constructed of two layers
of substrate (polyester/polyimide) film. On each layer, a conductive
material (silver) is applied, followed by a layer of pressure-sensitive
ink. Adhesive is then used to laminate the two layers of substrate
together to form the force sensor. The active sensing area is defined
by the silver circle on top of the pressure-sensitive ink. Silver
extends from the sensing area to the connectors at the other end
of the sensor, forming the conductive leads. A201 sensors are terminated
with male square pins, allowing them to be easily incorporated into
a circuit. The two outer pins of the connector are active and the
center pin is inactive.
How it Works
The FlexiForce single element force sensor acts as
a force sensing resistor in an electrical circuit. When the force
sensor is unloaded, its resistance is very high. When a force is
applied to the sensor, this resistance decreases. The resistance
can be read by connecting a multimeter to the outer two pins, then
applying a force to the sensing area. In the image below, the plot
shows both the Force vs. resistance and Force vs. conductance (1/R).
Note that the conductance curve is linear, and therefore useful
in calibration.
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One way to integrate the A201 force sensor into an application
is to incorporate it into a force-to-voltage circuit. A means of
calibration must then be established to convert the output into
the appropriate engineering units. Depending on the setup, an adjustment
could then be done to increase or decrease the sensitivity of the
force sensor. The chart to the right shows a typical sensor response
(based on the
recommended drive circuit).
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Sensor Response Graph
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Benefits
FlexiForce is renowned for its versatility, ease of
integration, and cost-effectiveness. FlexiForce sensors are pliable enough to allow for non-intrusive
measurement. They can be attached to many surfaces, and can be combined
with plastic or metal films for increased stiffness or for added
protection from abrasion.
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| Physical Properties |
| Thickness |
0.008" (.208mm) |
| Length |
8" (203mm)
6" (152mm)
4" (102mm)
2" (51mm) |
| Width |
0.55" (14mm) |
| Sensing Area |
0.375" diameter (9.53mm) |
| Connector |
3-pin male square pin |
| Thickness |
0.008" (.208mm) |
| Typical Performance |
| Linearity Error |
<+/-5% |
| Repeatability |
<+/-2.5% of full scale (conditioned sensor,
80% force applied) |
| Hysteresis |
<4.5% of full scale (conditioned sensor,
80% force applied) |
| Drift |
<5% per logarithmic time scale (constant
load of 90% sensor rating) |
| Response Time |
<5 microseconds |
| Operating Temperatures |
15°F to 140°F (-9°C to 60°C) |
| Force Ranges |
0-1 lb. (4.4 N)
0-25 lbs. (110 N)
0-100 lbs. (440 N)* |
| Temperature Sensitivity |
Output variance up to 0.2% per degree F (approximately
0.36% per degree C) |
| Documentation |
| Manual |
Download FlexiForce User Manual |