[nanoPost] ELONGATION SENSORS IN CONDUCTING TEXTILES FOR WEARABLE APPLICATIONS

Research Centre Spain

Hypothesis.
 

“The conducting material conductivity resistance changes when there is stretching produced by a force”

If we achieve a conducting knitting textile with measurable and manipulable elongation,  when this textile suffers deformation in a specific direction we will obtain a specific value of its conductivity resistance. If this property is always consistent, we can establish a relationship between conductivity and deformation. Therefore, doing this the opposite way round we can find out the level of deformation by measuring its resistance value.

During the first year of the project, the research has been focused on the construction of an intelligent fabric, which acts as touch screen and has been patented during the year 2005 . The fabric can be both knitted or woven with lycra, and has staple textile conductive yarns inserted inside it.In addition, in one of the headings, a detection electronic plaque has been integrated in such way that it is possible to measure the difference of superficial electrical conductivity established when a touch pressure is done above it, even the exact point where the pressure has been done can be measured. Several prototypes has been developed validating the efficacy and the technical and industrial feasability of the system.
 
In this second year of the project, the work carried out has been related to the research and development of a system able to measure the volume enclosed on a body through using this same intelligent elastic and conductive fabric, sending this way the information to an external receptor system and performing, with the help of a software, a treatment for the virtualisation in a screen of this closed volume . 
 
The main application of this volume quantitative measurement system will be destined to determine the corporal volume or corporal outline of the human body through a simple T-shirt or a tight elastic jeans. In such way , the pattern scaling will  be also directly obtained.

 
CONCLUSIONS

1. we have been able to obtain a relationship between the elongation and the conducting properties in a specific knitting textile.

2. this specific knitting textile has been obtained optimizing the variables:

- type of conducting yarn.
- different manufacturing structures.

3. We have been able to characterize the deformation in this type of intelligent textile with the conductivity value.

4. We have developed an electronic system to register the change of conductivity when there is deformation, to interpret the signal and to send it to an external receiver, where it is then displayed.

5. When this deformation is caused by physical pressure, it has been possible to detect the specific area of the textile affected by this pressure.

6. In the case of tactile pressure, it is possible to use this intelligent textile as a tactile screen.