FSR402 Resistive Film Pressure Sensor

FSR402 Resistive Film Pressure Sensor

Force Sensitive Resistor (FSR) – Thin Film Pressure Sensor

The FSR402 Resistive Film Pressure Sensor is a thin, flexible force-sensitive resistor (FSR) that changes its resistance when pressure or force is applied to its sensing area. It is designed for force, pressure, and touch detection, making it ideal for Arduino, ESP32/ESP8266, Raspberry Pi (via ADC), robotics, and human–machine interaction projects.

The sensor is lightweight, durable, and easy to integrate into compact or flexible designs.

Key Features

• Detects Force, Pressure, and Touch

• Thin, Flexible, and Lightweight Design

• Resistance Decreases with Applied Force

• Fast Response Time

• Low Power Consumption

• Simple Analog Interface

• Long Operational Life

Working Principle

The FSR402 operates on a resistive polymer film technology:

• With no pressure, the sensor has very high resistance.

• As force is applied, conductive particles inside the film move closer together.

• This causes the resistance to decrease proportionally to the applied force.

The sensor is typically used with a voltage divider circuit to convert resistance changes into an analog voltage readable by a microcontroller.

Technical Specifications (Typical)

• Sensor Type: Force Sensitive Resistor (FSR)

• Model: FSR402

• Sensing Area Diameter: ~12.7 mm

• Force Sensitivity Range: 0.2 N to 20 N (approx.)

• Resistance Range:

  • 1 MΩ (no force)

  • ~10 kΩ (high force)

• Response Time: < 5 ms

• Operating Temperature: −30°C to +70°C

• Thickness: < 0.5 mm

Electrical Characteristics

• Output Type: Analog (resistance-based)

• Interface: Two-pin connection

• Recommended Circuit: Voltage divider

Construction

• Sensing Head:

  • Circular pressure-sensitive area

  • Durable resistive polymer film

• Flexible Tail:

  • Printed conductive traces

  • Easy soldering or connector attachment

Applications

• Pressure and force measurement

• Touch and button sensing

• Robotics grip force detection

• Weight and load sensing (non-precision)

• Medical and rehabilitation devices

• Gaming controllers

• Wearable electronics

• Human–machine interaction (HMI)

• Educational electronics projects

Advantages

• Ultra-thin and flexible form factor

• No mechanical moving parts

• Simple interface and low cost

• Works with standard ADC inputs

• Suitable for embedded and wearable systems

Limitations (Important Note)

• Not intended for high-precision force measurement

• Output is non-linear

• Best suited for relative force detection, not calibrated weight scales