FSR 400 FORCE SMALL 5.08MM SENSOR CAPACTIVE

FSR-400 Small Force Sensing Resistor – 5.08mm Force Sensor

The FSR-400 Small Force Sensing Resistor is a compact, pressure-sensitive resistor designed to detect force applied to its small 5.08mm sensing area. Its compact size makes it suitable for applications where space is limited and a small force-sensitive element is required.

The resistance of the FSR changes according to the amount of force applied to its sensing surface. As the applied force increases, the electrical resistance generally decreases. This change can be measured using a suitable electronic circuit, allowing the sensor to be used for touch detection, pressure sensing, force detection, and interactive control applications.

The small sensing area makes the FSR-400 particularly useful for detecting pressure at a specific point rather than across a large surface. It can be integrated into robotic mechanisms, switches, control interfaces, wearable prototypes, and other compact sensing systems.

The FSR-400 is a passive resistive sensor, so it does not generate a digital signal by itself. Instead, an external measurement circuit can convert the resistance change into a voltage signal that can be read by a microcontroller or other electronic system.

Its simple operating principle and compact form factor make it convenient for Arduino, robotics, automation, DIY electronics, research, and prototype development.

Features

• Compact force sensing resistor
• Small 5.08mm sensing area
• Resistance changes with applied force
• Resistance generally decreases as force increases
• Thin and compact sensing element
• Suitable for point-pressure detection
• Simple resistive sensing principle
• Passive sensor design
• Easy to integrate into custom electronic circuits
• Suitable for microcontroller-based projects
• Useful for Arduino projects
• Suitable for robotics and automation
• Ideal for touch and pressure detection
• Useful for compact and space-limited applications
• Suitable for DIY electronics and prototyping

Specifications

Parameter	Specification
Product Type	Small Force Sensing Resistor
Model	FSR-400
Sensor Type	Force Sensitive Resistor (FSR)
Sensing Area	5.08mm
Output	Variable Resistance
Response	Resistance Changes with Applied Force
Sensor Type	Passive
Application	Force, Pressure and Touch Detection
Suitable Platforms	Arduino, Microcontrollers and Embedded Systems

Design and Construction

The FSR-400 is designed as a small force-sensitive resistive element with a compact sensing area of approximately 5.08mm. Its small footprint makes it suitable for integrating force detection into mechanisms and assemblies where a larger sensor would be difficult to install.

The sensor responds to mechanical pressure applied to its active sensing area. Rather than providing a conventional digital ON/OFF output, the FSR produces a variable resistance that changes according to the applied force.

This allows the sensor to be incorporated into custom measurement circuits and control systems. A microcontroller can monitor the resulting electrical signal and use it to detect touch, pressure, or changes in applied force.

Its compact construction makes the sensor particularly useful for applications requiring localized force detection.

Working Principle

The FSR-400 works by changing its electrical resistance when mechanical force is applied to the sensing area.

With little or no force applied, the sensor has a relatively high resistance. When pressure is applied, the resistance decreases. The amount of resistance change depends on factors such as applied force, contact area, sensor placement, and operating conditions.

A common method of reading an FSR is to connect it to a voltage-divider circuit. The resulting voltage changes as the sensor resistance changes.

A microcontroller such as an Arduino can then read this changing voltage through an analog input and use the information to determine whether pressure is being applied or to estimate relative changes in force.

The sensor is therefore suitable for applications where relative force or pressure detection is required.

Interfacing with a Microcontroller

The FSR-400 can be integrated with a microcontroller using a simple resistor network.

A typical voltage-divider circuit consists of:

• FSR-400 sensor
• Fixed resistor
• Microcontroller analog input
• Power supply

As the resistance of the FSR changes, the voltage at the analog input also changes. The microcontroller can monitor this voltage and respond according to the programmed force or pressure thresholds.

This makes the sensor convenient for projects using platforms such as Arduino and other compatible microcontrollers.

The exact resistor value and circuit configuration should be selected according to the desired sensing range and application requirements.

Touch and Pressure Detection

The small 5.08mm sensing area allows the FSR-400 to detect pressure at a localized point. This makes it useful for custom buttons, touch-sensitive mechanisms, robotic contact detection, and interactive controls.

For example, the sensor can be positioned beneath a mechanical surface so that pressing the surface applies force directly to the sensing area.

The resulting resistance change can then be detected by the control system.

Applications

• Robotics
• Robotic contact sensing
• Automation systems
• Touch-sensitive controls
• Pressure-sensitive switches
• Force detection
• Human-machine interfaces
• Arduino projects
• Microcontroller projects
• DIY electronics
• Interactive electronic systems
• Compact control interfaces
• Robotic mechanisms
• Grip and contact detection
• Wearable electronics prototypes
• Embedded sensing systems
• Educational electronics
• Research projects
• Experimental force sensing
• Mechanical prototypes
• Custom pressure detection systems

Important Considerations

The FSR-400 is intended primarily for force and pressure detection, rather than precision weighing or laboratory-grade force measurement.

The resistance response can vary depending on the force applied, contact area, mounting arrangement, environmental conditions, and sensor characteristics. For applications requiring accurate force measurement, appropriate calibration and application-specific testing are recommended.

Avoid applying excessive mechanical force beyond the sensor’s intended operating conditions, as improper handling can damage the sensing element.

Package Includes

• 1 × FSR-400 Small Force Sensing Resistor

Product Disclaimer

Product images are shown for illustrative and representational purposes only. The actual product may vary slightly in appearance, dimensions, markings, connector arrangement, or construction depending on the manufacturing batch.

The 5.08mm sensing area refers to the specified sensing region of the FSR-400. Actual sensing performance may vary depending on mounting conditions, contact area, applied force, and the measurement circuit.

This product is a passive sensing component and does not include a microcontroller, resistor, wiring, power supply, or other electronic components unless specifically mentioned in the package contents.

The FSR-400 is not intended to be used as a calibrated precision weighing sensor without appropriate calibration and application-specific compensation.

Recommended Related Products

Explore relevant force-sensing and pressure-sensing products available from TechyTron.

• Force Sensing Resistor – Square 44mm (FSR-406 Type)
• FSR-402 Force Sensitive Resistor – 14.7mm Round Pressure Sensor (100g–10kg)
• Force and Pressure Sensors – TechyTron Category