Networks of sensors show great promise as the basis for future technologies such as the Internet of Things (IoT) and wearable technology. However, key to them delivering on their promise is how well and efficiently they can communicate with each other to transmit data wirelessly.

Researchers at the National University of Singapore (NUS)—from left, PhD student Tian Xi, Research Fellow Lee Pui Mun, and Assistant Professor John Ho—spent a year developing smart textiles with unprecedented connectivity capability. (Image Source: NUS)

Currently, sensors typically use Wi-Fi or Bluetooth for this communication, which have some energy and other limitations as data becomes more sophisticated. To solve this issue, researchers at the National University of Singapore (NUS) have developed a new way for sensors to connect that they said provides a signal that’s 1,000 times stronger than conventional technology.

The team from the NUS Institute for Health Innovation & Technology and NUS Engineering—led by Assistant Professor John Ho —focused particularly on sensors for wearable technology, creating a wireless body sensor network that researchers said could be used for health-monitoring, medical, and human-machine interface applications.

“This innovation allows for the perfect transmission of data between devices at power levels that are 1,000 times reduced,” Ho said in a press statement. “Or, alternatively, these metamaterial textiles could boost the received signal by 1,000 times, which could give you dramatically higher data rates for the same power.”

The signal strength of the network is not only capable of transmitting data, researchers said. It also is strong enough to transmit energy that can power from a smartphone to the wearable device, precluding the need for a bulky battery, they said.

Localizing the Signals

A team of 10 researchers spent a year developing the technology, the key to which is to minimize the distance that the signals between the sensors need to travel to establish communication.

Radio waves used in technologies such as Bluetooth and Wi-Fi radiate outwards in all directions. This works sufficiently for communication; however, it also means that most of the energy is lost to the surrounding area, which reduces the efficiency of the wearable technology because making that connection consumes significant battery life.

Ho’s team decided to reduce this energy loss by enhancing clothing with conductive textiles known as metamaterials. These materials can create surface radio waves that glide wirelessly around the body on the clothes, holding the energy of the device signals close to the body rather than radiating them outward. This allows the devices to use much less power than is typical, allowing the sensors to detect weaker signals and thus communicate better, researchers said.

Specifically, researchers designed a comb-shaped strip of metamaterial that can be arranged in various patterns on top of the clothing with a conducting layer underneath. The metamaterial costs about a few dollars a meter and is available for purchase in rolls, making it cost-effective and accessible for researchers, Ho said.

“We started with a specific metamaterial that was both flat and could support surface waves,” he explained in the press statement. “We had to redesign the structure so that it could work at the frequencies used for Bluetooth and Wi-Fi, perform well even when close to the human body, and could be mass produced by cutting sheets of conductive textile.”

Another benefit of the technology is that the metamaterial can function with any existing wireless device in the designed frequency band, so it does not require any changes to either the smartphone or the Bluetooth device, Ho said.

The team published a cover story on the technology in the journal Nature Electronics.

Medical Uses and More

The smart clothing device Ho’s team designed is fairly durable and can be washed, dried, and even ironed like typical clothing, researchers reported. The device also can be folded and bent with minimal loss to the signal strength, and the conductive strips even when cut or torn do not show degradation in wireless capabilities, researchers said.

The team hopes to commercialize the technology through business partners as well as soon being testing the smart textiles in clothing form for hospital patients to provide a variety of advanced functionality, Ho said. This includes use in medical applications such as measuring vital signs to something a bit more practical that would come in handy for fitness buffs–adjusting the volume in wireless headphones with a single hand motion, he said.

“We envision that endowing athletic wear, medical clothing, and other apparel with such advanced electromagnetic capabilities can enhance our ability to perceive and interact with the world around us,” Ho said in the press statement.

 Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.

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