A stretch sensor is a
sensor
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
which can be used to measure
deformation
Deformation can refer to:
* Deformation (engineering), changes in an object's shape or form due to the application of a force or forces.
** Deformation (physics), such changes considered and analyzed as displacements of continuum bodies.
* Defor ...
and
stretching forces such as
tension
Tension may refer to:
Science
* Psychological stress
* Tension (physics), a force related to the stretching of an object (the opposite of compression)
* Tension (geology), a stress which stretches rocks in two opposite directions
* Voltage or el ...
or
bending
In applied mechanics, bending (also known as flexure) characterizes the behavior of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element.
The structural element is assumed to ...
. 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. Electric current is gener ...
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 parallels ...
changes (usually increases) substantially when the sensor is deformed.
The second type consists of a
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
for which the
capacitance
Capacitance is the capability of a material object or device 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 ...
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 mo-cap or mocap, for short) is the process of recording the movement of objects or people. It is used in military, entertainment, sports, medical applications, and for validation of computer vision and robo ...
glove (
data glove
A wired glove (also called a dataglove or cyberglove) is an input device for human–computer interaction worn like a glove.
Various sensor technologies are used to capture physical data such as bending of fingers. Often a motion tracker, such ...
) 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 an interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist humans. Robotics integrat ...
, particularly in
soft robots
Soft robotics is a subfield of robotics that concerns the design, control, and fabrication of robots composed of compliant materials, instead of rigid links.
In contrast to rigid-bodied robots built from metals, ceramics and hard plastics, the ...
.
See also
*
Flexible electronics
Flexible electronics, also known as ''flex circuits'', is a technology for assembling electronic circuits by mounting electronic devices on flexible plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Additi ...
*
Force gauge
A force gauge (also called a force meter) is a measuring instrument used to measure forces. Applications exist in research and development, laboratory, quality, production and field environment. There are two kinds of force gauges today: mechanica ...
*
Thermistor
A thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of ''thermal'' and ''resistor''.
Thermistors are divided based on their conduction ...
*
Stretchable electronics
Stretchable electronics, also known as elastic electronics or elastic circuits, is a group of technologies for building electronic circuits by depositing or embedding electronic devices and circuits onto stretchable substrates such as silicones or ...
*
Stretch receptor
Stretch receptors are mechanoreceptors responsive to distention of various organs and muscles, and are neurologically linked to the Medulla oblongata, medulla in the brain stem via Afferent nerve fiber, afferent nerve fibers. Examples include stre ...
References
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Sensors
Resistive components
Measuring instruments
Transducers