Flex sensors

Prototype flex sensors for wearables and medical devices

Flex sensors

Flex sensors

Prototype flex sensors for wearables and medical devices

A flex sensor, also known as a bend or flexion sensor, is a resistive device that changes its electrical resistance based on the degree of curvature. Common in wearable electronics, rehabilitation tools, and human-machine interfaces (HMI), flex sensors play a foundational role in gesture recognition [1].

Typically, flex sensors are constructed with conductive material, such as carbon or metal-based inks, on a flexible substrate. When straight, conductive particles are closer together, offering a certain baseline resistance. When bent, particles spread further apart, increasing the path length for electrical current, and thereby, increasing resistance.

APPLICABLE INDUSTRIES

  • Healthcare
  • Smart textiles
  • Consumer electronics
  • Automotive
  • Sensors

COMMON MATERIALS

  • Carbon: Nanotubes, graphite, nanoparticles
  • Transition metals: Silver, copper, nickel, platinum, palladium
  • Conductive polymer: Poly(3,4-ethylenedioxythiophene):PSS (PEDOT:PSS)

COMMON SUBSTRATES

  • Polymer-based: Polyvinylchloride (PVC), polypropylene (PP)
  • Elastic polymers: Silicone rubber, polyurethane (PU) rubber
  • Polyester: Polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN)
  • Fabric: Cotton, nylon, spandex

INDUSTRY

INDUSTRY

FUTURE OUTLOOK

FAST FACTS

Frequently asked questions

  • Yes. Alternatives include inertial measurement units (IMUs), fiber Bragg grating sensors, video-based tracking, and stretchable capacitive sensors. Each has trade-offs in cost, accuracy, and complexity:

    • IMUs provide comprehensive motion data but suffer from drift and require higher processing power.
    • Video-based tracking is powerful but faces challenges with lighting conditions, computational load, and privacy.
    • Capacitive sensors offer flexibility and conformability but often involve greater circuit complexity.
  • Flex sensors are fundamentally different from force-sensitive resistors (FSRs), though both are often used in HMI applications. Flex sensors measure bending or curvature; their resistance changes proportionally to the angle of flex. In contrast, FSRs respond to applied pressure or force; their resistance changes when direct perpendicular force is exerted on their active surface.

  • Yes. Alternatives include inertial measurement units (IMUs), fiber Bragg grating sensors, video-based tracking, and stretchable capacitive sensors. Each has trade-offs in cost, accuracy, and complexity:

    • IMUs provide comprehensive motion data but suffer from drift and require higher processing power.
    • Video-based tracking is powerful but faces challenges with lighting conditions, computational load, and privacy.
    • Capacitive sensors offer flexibility and conformability but often involve greater circuit complexity.
  • Flex sensors are fundamentally different from force-sensitive resistors (FSRs), though both are often used in HMI applications. Flex sensors measure bending or curvature; their resistance changes proportionally to the angle of flex. In contrast, FSRs respond to applied pressure or force; their resistance changes when direct perpendicular force is exerted on their active surface.

Learn how we can help with your application

This website uses cookies to improve user experience. By using our website you consent to all cookies in accordance with our cookie policy.