‘Pyjamas’, the smart pajamas that monitor and help you sleep better

Ordinary-looking pajamas are transformed into “smart” ones with five strategically placed sensors that measure heartbeat, respiration and posture. Photo credit: Courtesy of Trisha L. Andrew
Ordinary-looking pajamas are transformed into “smart” ones with five strategically placed sensors that measure heartbeat, respiration and posture. Photo credit: Courtesy of Trisha L. Andrew

Want a good night’s sleep? It is not as easy as it may seem. A good night’s sleep is the dream of every individual, but most people couldn’t get the one. There are many reasons for that, but one of the biggest could be work stress. Fortunately, these days there are plenty of aids to help with sleep problems.

And now, researchers have developed pajamas embedded with self-powered sensors that provide unobtrusive and continuous monitoring of heartbeat, breathing and sleep posture — all factors that play a role in how well a person slumbers. This smart garment called “Phyjama” could give useful information to help improve sleep patterns to ordinary people, as well as clinicians.

Trisha L. Andrew, Ph.D., who led the team says, “Our smart pajamas overcame numerous technical challenges,” says Trisha L. Andrew, Ph.D., who led the team. “We had to inconspicuously integrate sensing elements and portable power sources into everyday garments, while maintaining the weight, feel, comfort, function, and ruggedness of familiar clothes and fabrics.”

“We also worked with computer scientists and electrical engineers to process the myriad signals coming from the sensors so that we had clear and easy-to-understand information”, she added.

According to the National Institutes of Health, quality sleep can help protect people against stress, infections and multiple diseases like blood pressure, diabetes and heart disease. Besides, it also increases mental acuity and sharpens decision-making skills.

The researchers presented their results today at the American Chemical Society (ACS) Spring 2019 National Meeting & Exposition.

Image is adapted from the American Chemical Society video.
The image is adapted from the American Chemical Society video.

The key to smart pajamas is a process called reactive vapor deposition. “This method allows us to synthesize a polymer and simultaneously deposit it directly on the fabric in the vapor phase to form various electronic components and, ultimately, integrated sensors,” Andrew says.

“Unlike most electronic wearables, the vapor-deposited electronic polymer films are wash-and-wear stable, and they withstand mechanically demanding textile manufacturing routines”, she further explained.

The smart garment has five discrete textile patches with sensors in them. The patches are integrated using silver-plated nylon threads shielded in cotton.

Moreover, the wires from each patch end up at a button-sized printed circuit board placed at the same location as a pajama button. Data are wirelessly sent to a receiver using a small Bluetooth transmitter that is part of the circuitry in the button.

The “Phyjama” includes two types of self-powered sensors that detect “ballistic movements” or pressure changes. Four of the patches are piezoelectric. They detect constant pressures like that of a bed against a person’s body.

The triboelectric patch detects quick changes in pressure, such as the physical pumping of the heart, which provides information on heart rate. This is the first time such a sensor has been shown to detect tiny ballistic signals from the heart, researchers said.

For the study, the team tested the garment on volunteers and validated the readings from the sensors independently.

And now the researcher team is working on extending the technology to wearable electronic sensors that detect gait and send feedback to a monitor to help prevent falls.