Stanford engineers have developed a new type of wearable technology called BodyNet that detects physiological signals emanating from the skin. The novel tech consists of wireless sensors that stick like band-aids and beam readings.
Full body readings
BodyNet is the brainchild of Zhenan Bao, a chemical engineering professor. She believes the wearable technology will someday be used in medical settings to take full body readings.
"We think one day it will be possible to create a full-body skin-sensor array to collect physiological data without interfering with a person's normal behavior," said Bao, who is also the K.K. Lee Professor in the School of Engineering.
The sensors were three years in the making. The ultimate goal was to develop a technology that would be comfortable to wear while having no circuits that would prevent the stickers from stretching with the skin.
To achieve this the team used a variation of the RFID technology. RFID or radiofrequency identification is what enables keyless entry to locked rooms.
When an ID card is held up to an RFID receiver, an antenna in the ID card harvests RFID energy from the receiver and uses this to generate a code that it then beams back to the receiver. BodyNet stickers function like these ID cards.
They have an antenna that harvests a bit of the incoming RFID energy from a receiver on the clothing to power its sensors. They then take readings from the skin and beam them back to the nearby receiver.
As such, the researchers had to deal with one key complication. They needed an antenna that could stretch and bend like skin.
A new type of RFID
To bypass this obstacle, they screen-printing metallic ink on a rubber sticker. "However, whenever the antenna bent or stretched, those movements made its signal too weak and unstable to be useful.
To get around this problem, the Stanford researchers developed a new type of RFID system that could beam strong and accurate signals to the receiver despite constant fluctuations. The battery-powered receiver then uses Bluetooth to periodically upload data from the stickers to a smartphone, computer or other permanent storage system," said Stanford's press release.
For now, the stickers produce respiration and pulse readings but the team hopes to integrate sweat, temperature and other sensors into their antenna systems.
The study is published in the journal Nature Electronics.