In-Depth: Interfacing Flex Sensor with Arduino

At the heart of this project is a flex sensor, which acts as a variable resistor whose internal resistance changes depending on how much it is bent. Because an Arduino Uno cannot directly measure changes in resistance with its digital pins, we use an analog input pin. To convert the changing resistance of the flex sensor into a measurable voltage change, the sensor is paired with a fixed 47kΩ resistor to form a simple voltage divider circuit. One end of the flex sensor connects to the positive voltage supply (5V), while the other connects to the 47kΩ resistor, which then ties to ground (GND). The junction point between the flex sensor and the fixed resistor is wired to one of the Arduino's analog-to-digital converter (ADC) pins. When the flex sensor bends, its resistance increases, altering the voltage drop across the circuit. The Arduino reads this shifting analog voltage level and converts it into a digital value via its internal ADC. Using the Arduino IDE software, you can write code to monitor these raw analog values, allowing you to translate the degree of physical bending into meaningful data for various telemetry, remote logging, or IoT applications.