Force Sensitive Resistor 1.5″ 25.4mm FSR Flexible Pressure Sensor RP-S40-LT

Force Sensitive Resistor 1.5″ (25.4 mm)

RP-S40-LT Flexible Pressure Sensor

Large-Area Force & Pressure Detection Sensor

The RP-S40-LT Force Sensitive Resistor (FSR) is a thin, flexible pressure sensor with a large 1.5-inch (25.4 mm) square sensing area, designed to detect force, pressure, and touch. Its resistance decreases as applied force increases, allowing easy pressure measurement using simple analog circuits.

This sensor is ideal for Arduino, ESP32/ESP8266, Raspberry Pi (via ADC), robotics, wearable electronics, and human–machine interaction systems where large-area pressure detection is required.

Key Features

• Large 1.5″ (25.4 mm) Square Sensing Area

• Flexible & Ultra-Thin Film Design

• Detects Force, Pressure, and Touch

• Fast Response Time

• Low Power Consumption

• Simple Analog Interface

• Durable & Lightweight Construction

Working Principle

The RP-S40-LT works on resistive polymer technology:

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

• When force is applied, conductive particles inside the polymer layer move closer together.

• This causes the resistance to drop proportionally with applied pressure.

Using a voltage divider, these resistance changes can be converted into an analog voltage that a microcontroller can easily read.

Technical Specifications (Typical)

• Sensor Type: Force Sensitive Resistor (FSR)

• Model: RP-S40-LT

• Sensing Area Size: 1.5″ × 1.5″ (25.4 mm × 25.4 mm)

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

• Resistance Range:

  • 1 MΩ (no load)

  • ~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)

• Connection: 2-pin flexible tail

• Recommended Circuit: Voltage divider with fixed resistor

Construction & Design

• Large Square Sensing Pad:

  • Even pressure distribution

  • Suitable for foot, hand, or object pressure detection

• Flexible Tail Connector:

  • Printed conductive traces

  • Easy soldering or connector mounting

• Protective Film Layers:

  • Ensures long service life

Applications

• Pressure mats and footstep detection

• Robotics grip and load sensing

• Touch and human–machine interfaces

• Smart seats and posture monitoring

• Medical and rehabilitation devices

• Gaming and interactive systems

• Wearable electronics

• IoT-based pressure monitoring

• Educational electronics projects

Advantages

• Large sensing area for uniform pressure detection

• Ultra-thin and flexible form factor

• No mechanical moving parts

• Easy integration with microcontrollers

• Cost-effective pressure sensing solution

Limitations (Important Note)

• Not suitable for high-precision force measurement

• Output is non-linear

• Best used for relative force detection, not calibrated weighing systems