Bend Sensor

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Added Environmental Protection

The Bend Sensor® product consists of a coated substrate, such as plastic, that changes in electrical conductivity as it is bent. Electronic systems connect to the sensor and measure with fine detail the amount of bending or movement that occurs. The single-layer design of the Bend Sensor® eliminates many of the problems associated with conventional sensors, such as dust, dirt, liquids, and heat and pressure effects. Over-laminates or over-molding may also be applied to the sensors for added environmental protection. Flexpoint Sensor Systems offers standard designs and can also custom design and engineer a sensor that meets the dimensions and requirements of your application.

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Frequently Asked Questions

Based on a test set up with a 90° bend on a ¼" [6mm] radius, the Polyimide based sensors will complete > 30 million cycles, and Polyester-based sensors will complete >10 million cycles.

   

A standard Bend Sensor will constantly function between 100°C and -40°C. With some modifications, we are able to get to 200°C and to -60°C

   

This depends on the circuit used to read the sensor. We have used 12, 5, and ~3VDC in the designs we have developed.

   

Change in resistance is a function of bend radius and angular deflection. The sensor will also change if stretched linearly. Changes greater than 100X are possible.

   

The sensors have been soaked in gasoline, diesel fuel, DOT3 brake fluid, antifreeze, alcohol, motor oil, and colas without detrimental effects on the sensor. Solvents like acetone and methyl ethyl ketone will dissolve some of the inks and destroy the sensor.

   

The sensor is basically a variable resistor. Typically it only has two leads. In a microprocessor-based circuit, the sensor is set up in a voltage divider, and the change in voltage is read by the processor using an ADC. There are some processors that have an integrated current DAC to bias the sensor with a constant current. The voltage across the sensor is then measured using the microprocessor's ADC.

   

Under controlled circumstances, it is about +/-3%

   

Humidity will affect the sensor. It is very repeatable and predictable. Flexpoint has a patent issued based on using the sensor as a humidity indicator.

   

The bend radius is limited by the material the sensor is printed on. Once the elastic limits of the substrate are exceeded, then the sensor is damaged.

   

FSRs are multiple layers that interact with one another. The resting resistance is generally quite high if not open, and when the layers are compressed together, the resistance decreases. The Bend Sensor is a single-layer construction. It starts at a relatively low resistance when flat and increases as it is bent.

   

Piezo Sensors typically will give a voltage output when it is bent. Once motionless, the sensor gives no feedback until it is moved again. The Bend Sensor will hold its higher resistance value when bent and return to the lower resistance value when returned to its flat state.

   

Yes, we have a bi-directional version that uses sensor material on both sides and has a three-pin connection. This sensor will give you the resistance change in each direction independently.

   

Yes. Custom sensors can be individually monitored.

   

Currently, the Bend Sensor is printed on Polyester and Polyimide (Kapton) materials.

   

The minimum length is about .25" [6mm] plus the connector. The maximum length is equipment limited to 30" [760mm]. The width limitations are about .10" [2.54mm]

   

To arrange for a custom sensor, please contact Flexpoint directly. You can then discuss your application and sensor design to fit your requirements. If necessary, NDAs can be signed in advance.