With the recent technology boom, the demand for lightweight, smart and IoT enabled componentry has increased massively, hence the increased demand for FSR Sensors. These paper-thin sensors have saturated our everyday lives providing the simple innovative solutions that have been needed in a variety of industry. Product designers, engineers and innovators often opt for the flexibly printed force sense resistors due to their size and versatility. Reid Print Technologies manufactures FSR or Force Sensing Resistors to order, with a multitude of resistances, sizes, shapes and configurations on offer.
What are they?
Simple, thin, and flexible. Force Sensing Resistors, also widely known as FSR’s for short, are a resistive sensor that responds to a force that is applied to the active sensing area. In simple terms, a FSR is a sensor that’s resistance changes when pressure is applied to it. FSR’s consist of multiple thin and flexible substrates that have been electronically printed into specific configurations with specialised inks. The force or pressure data that has been collected through the sensors are then measured to give valuable feedback, supplying critical data across a wide variety of industry. Electronically printed FSRs are low cost and versatile to manufacture in a range of sizes, shapes and configurations. This also provides the added advantages of allowing for full customisation where needed.
How are Force Sensing Resistors made?
Force sense resistors by Reid Print Technologies are screen printed onto a flexible substrate with specialised carbon inks. This specialised ink enhances the sensor’s ability to measure the pressure or forces that are applied the active area of the sensors.
What are Force Sensing Resistors used for?
FSRs were created 1977 for musical instruments. Since then, FSR applications have expanded exponentially. You can find FSR technology in a variety of industry including:
- Internet of Things
- Wearable Technology
In simpler terms, if there is a need for pressure or force to be measured, force sense resistors can offer an economical, low cost and innovative solution.
What is the difference between Shunt Mode and Thru Mode?
It is important to understand that force sense resistors have two main types, shunt mode resistors and thru mode resistors.
Shunt Mode: Shunt Mode FSR’s are the most frequently used of the FSR family. These resistors are more receptive to a wider range force. The shunt mode FSR is made up of two layers of flexible substrate. Shunt Mode Force Sense Resistors are made by screen printing interdigitated track patterns on one film substrate and the force sensitive elemental ink is screen printed on the another. Each different FSR application requires different configurations and different design materials including the choice of silver, carbon, copper and other ink blends. However, silver conductive ink is the most common material for the shunt mode FSR.
Thru Mode: Thru Mode Force Sense Resistors are manufactured by screen printing a solid conductive pad on each substrate, layered with a force sensitive element faced towards each other. Thru Mode Resistors are more receptive to lighter forces. Although thru mode force sense resistors are less commonly used than the shunt mode, they are the preferable mode when aiming to detect the smaller forces. This is the due to more ink that is required to print the active area of a thru mode FSR. However, with the more ink required, the higher the price point of manufacturing the Thru Mode FSR.