We've already heard about touch-sensitive clothing that could be used to control devices via touchscreen-like finger taps and swipes on the fabric. The tech sounds impressive, but it does have some limitations. That's where a new "touchless" finger-gesture-detecting fabric comes in.
The experimental textile is being developed by scientists from Nottingham Trent University in the UK, the Helmholtz-Zentrum Dresden-Rossendorf research lab in Germany, and the Free University of Bozen-Bolzano in Italy.
So how does it work?
Well, the general idea is that if the technology were integrated into part of a garment, the wearer could perform tasks such as turning on appliances, answering phone calls, or operating smart TVs, all just by moving their index finger in the air space above the material.
In a current prototype version of the system, the user wears a ring with a 3 x 5-mm magnet upon it, on their index finger.
That ring emits a magnetic field, which affects the electrical resistance of four magnetoresistive sensors that are woven into a polyester sleeve. By comparing the extent to which the field simultaneously affects the resistance of each sensor, a linked microprocessor is able to determine the real-time three-dimensional position of the finger in the space above the sleeve.
Different finger positions/movements are assigned to different commands, which are relayed to a wirelessly linked electronic device. In the prototype system, the wearer is able to turn to either side or move forward in a VR environment via simple finger gestures.
Each of the sensors incorporates a small sheet of polyimide foil which is covered in layers of copper and cobalt. That sheet gets rolled up around a thin electrical wire then encapsulated in a polyester sheath, forming an individual braid that gets woven into the fabric. In lab tests, the sensors remained operational even after seven machine-wash laundry cycles.
By contrast, capacitive textile sensors that actually have to be touched tend to be much more fragile plus they're typically less flexible, making the augmented "smart" clothing more uncomfortable to wear. They may also be triggered accidentally as they rub against the user's skin while the person moves around.
And finally, the capacitive touch sensors don't work underwater or when otherwise wet – such as in the rain, or during sweaty activities – which isn't a problem for the new touchless sensors.
"Our design could revolutionize electronic textiles for both specialized and everyday clothing," says the lead scientist, Nottingham Trent University's Dr. Pasindu Lugoda. "It is machine washable and durable and does not impact the drape, or overall aesthetic appeal of the textile."
A paper on the research was recently published in the journal Communications Engineering.
Source: Nottingham Trent University
