A stretch sensor is a

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

which can be used to measure deformation and stretching forces such as tension or

bending In applied mechanics, bending (also known as flexure) characterizes the behavior of a slender structural element subjected to an external Structural load, load applied perpendicularly to a longitudinal axis of the element. The structural eleme ...

. They are usually made from a material that is itself soft and stretchable. Most stretch sensors fall into one of three categories. The first type consists of an

electrical conductor In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge (electric current) in one or more directions. Materials made of metal are common electrical conductors. The flow of negatively c ...

for which the

electrical resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual paral ...

changes (usually increases) substantially when the sensor is deformed. The second type consists of a

capacitor In electrical engineering, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. The capacitor was originally known as the condenser, a term st ...

for which the

capacitance Capacitance is the ability of an object to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related ...

changes under deformation. Known properties of the sensor can then be used to deduce the deformation from the resistance/capacitance. Both the rheostatic and capacitive types often take the form of a cord, tape, or mesh. The third type of sensor uses high performance piezoelectric systems in soft, flexible/stretchable formats for measuring signals using the capability of piezoelectric materials to interconvert mechanical and electrical forms of energy.

Applications

Wearable stretch sensors can be used for tasks such as measuring body posture or movement. in 2018, New Zealand based company StretchSense began making a

motion capture Motion capture (sometimes referred as mocap or mo-cap, for short) is the process of recording high-resolution motion (physics), movement of objects or people into a computer system. It is used in Military science, military, entertainment, sports ...

glove ( data glove) using stretch sensors. Unlike gloves that use inertial or optical sensors, stretchable sensors do not suffer from drift or occlusion. They can also be used in

robotics Robotics is the interdisciplinary study and practice of the design, construction, operation, and use of robots. Within mechanical engineering, robotics is the design and construction of the physical structures of robots, while in computer s ...

, particularly in soft robots. Stretch sensors are now widely used in medical fields for analysis and measuring the human dielectric properties w.r.t skin.

References

{{Reflist Sensors Resistive components Measuring instruments Transducers

Applications

See also

References