Introduction The bending sensor is a 7.3 cm long strip whose resistance varies when bent. It can bend from 0 degrees to 180 degrees.Flex sensors are available in two sizes: 2.2 inches (5.5 cm) long and 4.5 inches (11.4 cm) long. It can be useful in many areas:It can measure mechanical movement, air flow, water flow and even vibrations.It can be used as a motion sensor or as a highly resistant and reliable switch. How does the sensor work? One side of the sensor is printed with a polymer ink containing conductive particles. When the sensor is straight, the particles give the ink a resistance of around 30k Ohms.When the sensor is bent away from the ink, the conductive particles move further away, increasing this resistance (to around 50k-70k Ohms when the sensor is bent at 90 degrees, and up to 125k Ohms at 180 degrees). Sensor pins Here are the pins of the bending sensor:GND: Connect to the ground of the Arduino board.Vcc : To be connected to the arduino board with a 10k ohms resistor. Display value on serial monitor We’ll now look at how to display sensor deflection on the serial monitor. Blink the led with the flex sensor Here’s a circuit to vary the intensity of the LED according to the bending of the sensor. When the sensor is at 0°, the LED is off, but the closer the bending sensor is to 180°, the brighter the LED. Controlling a servomotor with the sensor The last circuit we’re proposing allows you to adapt the rotation of a servomotor with a bending sensor. In fact, it’s quite possible that these two components will be used together in your project to, for example, maintain the balance of a robot by adapting the position of the servomotor if the sensor is more or less twisted.Here, the servomotor is at position 0° when the sensor is not bent, and 180° when the sensor is completely bent.