FSR402 Resistive Thin Film Pressure Sensor

Connect one FSR402 lead to the Arduino's 5V (or 3.3V) supply and the other lead to an analog input pin (e.g., A0). Place a fixed-value resistor (typically 10kΩ) between the analog pin and ground to form a voltage divider. The voltage at the analog pin will vary with the applied force, which your code can read using analogRead().

The FSR402 provides a variable resistance output. Its resistance is very high (several Megohms) when no force is applied and decreases non-linearly as force increases, down to a few hundred ohms at maximum force. It does not output a standard voltage or digital signal directly; you must use an external circuit (like a voltage divider) to convert the resistance change into a measurable analog voltage.

The FSR402 is excellent for detecting the presence of force, relative changes in pressure, and threshold-based activation. For precise, absolute force measurement (e.g., in grams or Newtons), individual sensor calibration is required due to unit-to-unit variations and the non-linear resistance-to-force relationship. It is best used in applications where relative pressure or touch detection is sufficient.

The FSR402 itself does not have a specific operating voltage; it is a passive resistive component. The voltage applied across it in your circuit (e.g., 3.3V or 5V from your microcontroller) should be compatible with the rest of your measurement system, particularly the ADC reference voltage of your microcontroller. Avoid applying voltages that would cause excessive current through the sensor at low resistance states.