Engineers involved in the STRETCH program in the US are set to test a cloth interwoven with microelectronic components which functions as a sensitive battlefield sensor.
The STRETCH program is a co-operative venture between the University of Southern California and Virginia Tech that is working on a prototype ‘e-textile’, which is a cloth interwoven with microelectronic components.
The cloth is said to function as a sensitive detection array to pinpoint sources of faint sounds, specifically, the sounds of distant vehicles moving on future battlefields. According to its creators, STRETCH is the first time an e-textile has been produced that can perform all aspects of such a complicated process.
‘Modern methods of making fabrics allow extraordinary control over materials and properties,’ said Robert Parker, director of the Arlington, Virginia campus of the USC School of Engineering’s Information Sciences Institute, and co-principal investigator on STRETCH. ‘And cloth has properties that can be very useful for certain electronic applications. We can easily and cheaply make very large pieces of cloth, light and very strong, that can be stretched over frames into any desired shape.’
Modern methods of detection use arrays of individual detectors, arranged in a pattern, and combine the reports from all into a detailed image using computational algorithms.
Parker and his colleagues been working on arrays made up of small, standalone detectors that are individually placed in the environment, and communicate with each other by radio.
But embedding similar units into fabric has advantages, according to Parker. ‘The signals they exchange can be carried on wires in the fabric. This greatly lowers the power requirements to operate the system.’
Additionally, signal exchanges by radio can potentially be picked up by an adversary, giving away not only the fact that surveillance is underway, but also the position of those doing the surveillance.
‘Forming it into a fabric makes it electronically silent.’ said Jones. Additionally, while embedding the detectors in fabric sacrifices the flexibility of individual standalone units, it ensures the units will be automatically be in the right positions relative to each other to do their jobs optimally.
The STRETCH fabric will begin testing in field environments in November. Many problems have to be resolved. As Parker notes, ‘while fabric manufacturing technology is advanced, we expect that the large number of components and the inherent imprecision in the process will make it difficult to weave very large, fault-free arrays.’
Making these tough enough to stand up to weather and rough handling in field conditions is another challenge.
However, in preliminary tests, the material has proven robust. It can be rolled (though not folded) and unrolled, without damage. And even when numbers of the individual units fail, the detector is still able to function effectively.