ELI5: Explain Like I'm 5

Stretch sensor

A stretch sensor (also sometimes called a strain sensor) is a device that measures how much something is stretched or bent. It can tell you this because it has a special material inside that changes in a particular way when something is stretched. When something stretches the material inside the stretch sensor, it makes an electric signal that can be used to measure how much the thing was stretched. It’s like a measuring tape for stretch!