How to Choose Force Sensitive Sensors (FSR) & Thin Film Pressure Sensors

From smart wearables and robotic skins to industrial monitoring, Force Sensitive Resistors (FSR) and Thin Film Pressure Sensors are essential components for tactile feedback. DFRobot stocks a comprehensive range of force sensors from various industry-leading manufacturers. However, with so many options available in our marketplace, choosing the right one can be tricky.

This guide categorizes the sensor lineup available at DFRobot by performance, application, and budget to help you find the perfect match for your project—whether you are building a rugged industrial device or a classroom prototype.
 

Quick Decision Matrix: Which Sensor Do You Need?

Tier 1: The Game Changer (High Performance)

For professional engineers and industrial applications requiring durability.

[SEN0684] Ultra-Thin Circular Graphene Force Sensor

"A unique, solderable FSR option available in our catalog."

This is a premium addition to the store. Unlike traditional FSRs that often rely on fragile crimp connectors and melt under heat, this graphene-based sensor is designed for more demanding integrations.

Best For: Automotive (engine bays), industrial machinery, permanent installations, and high-vibration environments.
 

Key Advantages:

• High-Temperature Resistance: Operates reliably from -40°C to +120°C.
• Solder-Friendly: The unique tab material supports direct soldering, eliminating loose connections common in standard FSRs.
• Fast Response Time: <1ms
• Improved Repeatability: Offers better consistency compared to standard budget FSRs.
• Specs: Range: 20g-6kg | OD: 8mm | Thickness: 0.45mm

Figure: Ultra-Thin Circular Flex Force Sensor (0.45mm, 20g-6kg Range, 120°C High-Temp Resistance)

Tier 2: The "RP Series" (Best Value & Versatility)

The Sweet Spot: High sensitivity, ultra-thin profile, and affordable pricing ($3 - $10).
Note: These sensors come in "Short Lead" (ST) and "Long Lead" (LT) versions. We generally recommend Long Leads (LT) for easier integration.
 

1. Button & Finger Press (Circular)

Ideal for HMI (Human-Machine Interfaces), smart buttons, and robotic fingertips.

• Top Pick: [SEN0295] 18.3mm (Long Leads) * Why: The extended leads make wire routing significantly easier inside enclosures.

Figure: Circular Force Sensor with Extended Leads (Diameter: 18.3mm, 20g-6kg, Thickness: 0.4mm)

• Compact Pick: [SEN0298] 7.6mm (Long Leads) * Why: Perfect for tight spaces like inside a stylus or wearable device.

Figure: Circular Force Sensor with Extended Leads (Diameter: 7.6mm, 30g-1.5kg, Thickness: 0.3mm)

2. Surface & Edge Detection (Square & Strip)

Ideal for smart furniture, medical devices, and fluid level monitoring (via clamp pressure).

• [SEN0296] Square (40x40mm): Best for seat occupancy detection (smart cushions).

Figure: Square Force Sensor (40x40mm, 20g-10kg, Thickness: 0.45mm)

• [SEN0299] Long Strip (400mm): Best for smart mattresses (sleep tracking) or safety pinch-guards on automatic doors.

Figure: Pressure Sensor Strip (400mm, 20g-10kg)

• [SEN0293] Pressure Sensor Strip (170mm, 20g-10kg): Suitable for robotic grippers or shorter edge protection.

Figure: Pressure Sensor Strip (170mm, 20g-10kg)

Tier 3: Specialty & Legacy Solutions

The Heavy Lifter: [SEN0066] FlexiForce Pressure Sensor (Ø9.53mm, 0–45kg)

• Pros: Measures up to 45kg (100lbs), highly consistent, well-documented industrial heritage.
• Cons: Higher cost (~$22).
• Verdict: Use this for impact testing, weight distribution, or heavy machinery load monitoring where cheap sensors would saturate immediately.

Figure: FlexiForce Pressure Sensor (Ø9.53mm, 0–45kg, Industrial Grade)

The Classroom Classic: [SEN0065 - 4mm Mini Circular Force Sensor] & [SEN0047 - 0.5" Circular Force Sensor (100g-10kg)]

The original FSRs.

• Pros: Breadboard Friendly. They feature sturdy 2.54mm pitch pins that plug directly into a breadboard.
• Cons: Lower accuracy ("not for scale use"), thicker profile, and older technology compared to the RP series.
• Verdict: Excellent for STEM education and rapid Arduino prototyping where soldering is not an option. For production, switch to the RP series or SEN0684.

Figure: 4mm Mini Circular Force Sensor

Figure: 0.5" Circular Force Sensor (100g-10kg)

FAQ: Common Questions about FSRs

Q: Can I use these sensors as a weighing scale? 

A: Generally, no. FSRs are designed for qualitative force sensing (how hard am I pressing?) rather than quantitative weighing (exactly how many grams?). For precision weighing, please check the Gravity: I2C 1Kg Weight Sensor Kit in our store.

Q: How do I connect the RP Series (Tier 2) to my microcontroller? 

A: The RP series uses flexible flat tails. They are not designed for soldering; direct soldering will typically damage the tail. We recommend using an FPC connector, alligator clips, or carefully crimping them.

Q: What is the difference between Static and Dynamic pressure sensing? 

A: Static is a constant load (like sitting on a chair). Dynamic is a changing load (like tapping a finger). Our Graphene (SEN0684) and RP Series excel at both, with fast response times (<10ms).