Stretch sensor
A stretch sensor is a sensor which can be used to measure deformation and stretching forces such as tension or bending. 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 for which the electrical resistance changes (usually increases) substantially when the sensor is deformed.<ref>"Conductive Rubber Cord Stretch Sensor + extras!". Adafruit Industries. Retrieved 2019-06-07.</ref>
The second type consists of a capacitor for which the capacitance changes under deformation.<ref>"Master The Fundamentals Of Stretch-Sensor Sensitivity". Sensors Magazine. 11 November 2016. Retrieved 2019-06-07.</ref><ref>StretchSense. {{cite book}}: |work= ignored (help)</ref> 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.<ref name="Dagdeviren">Dagdeviren, Canan; Joe, Pauline; Tuzman, Ozlem L.; Park, Kwi-Il; Lee, Keon Jae; Shi, Yan; Huang, Yonggang; Rogers, John A. (2016). "Recent progress in flexible and stretchable piezoelectric devices for mechanical energy harvesting, sensing and actuation". Extreme Mechanics Letters. 9 (1): 269–281. doi:10.1016/j.eml.2016.05.015.</ref>
Applications
Wearable stretch sensors can be used for tasks such as measuring body posture or movement.<ref>"Disposable Skin Stretch Sensor". TU Delft. Retrieved 2019-06-07.</ref><ref>Huang B, Li M, Mei T, McCoul D, Qin S, Zhao Z, Zhao J (November 2017). "Wearable Stretch Sensors for Motion Measurement of the Wrist Joint Based on Dielectric Elastomers". Sensors. 17 (12): 2708. Bibcode:2017Senso..17.2708H. doi:10.3390/s17122708. PMC 5751736. PMID 29168775.</ref> in 2018, New Zealand based company StretchSense began making a motion capture glove (data glove) using stretch sensors.<ref>"StretchSense".</ref> Unlike gloves that use inertial or optical sensors, stretchable sensors do not suffer from drift or occlusion.
They can also be used in robotics, 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.<ref>Rangaiah, Pramod K. B.; Mandal, Bappaditya; Avetisyan, Erik; Chezhian, Arvind Selvan; Augustine, Bobins; Perez, Mauricio David; Augustine, Robin (2022). "Preliminary Analysis of Burn Degree Using Non-invasive Microwave Spiral Resonator Sensor for Clinical Applications". Frontiers in Medical Technology. 4: 859498. doi:10.3389/fmedt.2022.859498. ISSN 2673-3129. PMC 9037089. PMID 35479303.</ref>
