## Force and Flex Sensors ### Force-Sensitive Resistors [Force Sensitive Resistor](https://www.interlinkelectronics.com/standard-products) (FSR): compliant sheet material that reduces resistance when pressed, making it suitable for wearable applications. <!-- => Piezoresistivity (Piezo: from Ancient Greek πιέζω, “to press”). --> ![FSR](./fsr.jpg) As this kind of material acts as a variable resistor, it is appropriate to use a voltage divider circuit. One such material is known as [Velostat](https://www.adafruit.com/product/1361). See [examples from Hannah Perner-Wilson](https://cdn-shop.adafruit.com/datasheets/HandcraftingSensors.pdf). ### Flex Sensors Commercially available flex sensors are popular for Arduino projects, but are quite costly ($10-20). (See [hookup guide](https://learn.sparkfun.com/tutorials/flex-sensor-hookup-guide/all) from SparkFun). ![flex](./flex.jpg) Consider <a href ='https://elizabethgallardo.github.io/PHYSCI-70/Week%2006_Electronic%20Input%20Devices/index.html'>making your own flex sensor instead using a phototransistor</a>.