Initial report by Hsiao-Ho Hsu, Oct. 3 2005. Edited by Hanny Ahern and Lia Martinez, January 2012

The Merlin Stretch Sensor is a new way to measure stretch, displacement, compression and force.It is a flexible cylindrical cord with spade electrical fixings at each end. The sensor behaves like a variable resistor, the more you stretch it the higher the resistance. Release the elastic and the resistance returns to normal. Source.

Applications

Stretch Sensor can act like muscle contraction, and can be easily applied to any wearable design.

    Robotics
    Biometric displacement reading
    VR Gloves and VR suits
    Physics applications and experiments
    Feedback sensor for air muscles
    Breath sensing
    basic variable resistor
    soft wearable variable resistor

Electrical Characteristics

datasheet here

A fresh 19 cm stretch sensor gives out 5k Ohms when resting, 22k Ohms when fully stretch(appox 40 cm)
A kinda-old 21.5 cm stretch sensor gives out 13.5K Ohms when resting, 60kOhms when fully stretch(appox 55cm)

As the length of the Stretch Sensor alters so does its resistance. For each centimetre of length change there is a a change in resistance of about 400ohms.

Pin Descriptions

It acts like a variable resistant, just plug one into the ground and another into pic.

Microcontroller Connections

Code Sample

Stretch Sensor use raw data in
Stretch Sensor with an amp bridge

Typical Behavior

According from data sheet, as the length of the Stretch Sensor alters so does it's resistance. For each centimeter of length change there is a resistance change of approximatly 400 Ohms/cm.

Application Notes

Since stretch sensor is made by rubber, it gets loose and increase the resistance after a certain time.

http://notsimplyyes.com/SW/datasheetreading.htm