Stretch sensor is elastic, ultra-thin and lightweight, which could be used in extension measurement, especially suitable for objects that are elastic, flexible or have soft, uneven surface, round shape, curved angle, etc. 
 
Stretch sensor can be embedded in a wearable breathing monitoring device (a belt or a strap), and detect the physical extension of inhalation and exhalation, causing changes in capacitance.
 
The capacitance can be calculated and visualized as users' breathing data (as the application example showed above), through these data, users will have a better understanding of their breathing conditions, and will bring awareness and train their breath consciously.