People with chronic insomnia will sometimes undergo sleep studies, in which they slumber in a clinic while wired up to various sensors – perhaps not the best way to replicate their typical sleeping environment. Soon, however, they may simply be able to wear special electronic pyjamas, which are currently in development.
Led by Dr. Trisha L. Andrew, researchers at the University of Massachusetts-Amherst started with a regular set of pyjamas. Utilizing a technique known as reactive vapor deposition, they proceeded to simultaneously synthesize a polymer and deposit it onto the fabric, in vapor form. This allowed them to create five sensor-equipped textile patches on the inside of the jammies.
Four of these patches are piezoelectric, meaning that they generate an electrical current (which powers them) when subjected to mechanical stress. These measure the pressure of the wearer's body against the bed in four locations, in order to determine their sleeping posture.
The other patch is triboelectric, meaning that it becomes electrically-charged when it's rubbed against another material. It detects the wearer's heartbeat and rate of respiration, based on the quick changes in pressure that those processes place upon the sensors.
All five patches are electrically linked to one another via silver-plated nylon threads shielded in cotton, plus they're also linked to a button-sized printed circuit board that takes the place of one of the buttons. That device additionally incorporates a Bluetooth transmitter, which wirelessly relays sensor data to a nearby computer for analysis.
Known as the Phyjama, the resulting washable prototype garment has been lab-tested on volunteers, where readings from its patches were found to closely match those obtained by more traditional sleep-clinic sensors.
Andrews is now looking for a partner company to help commercialize the technology, and hopes to have a product on the market within a couple of years. She estimates a price of US$100 to $200 a set.
Source: American Chemical Society