In order for wearable Health Tech devices to “disappear” into our lives, they will have to do their jobs with a minimum amount of attention from the user. That means that they won’t have to be plugged in to recharge them every night (or every week or even every month). And they won’t have to be connected to some other device in order to exchange recorded data and other information. And all of this requires power. One solution is to make the power storage — such as batteries — larger, but this makes the device larger and potentially more intrusive. Another approach is to reduce the amount of power required to operate.

One large part of the energy budget for most wearables is the wireless communications. Even with low-power Bluetooth, the device has to transmit radio frequency (RF) emissions and that takes power. (Think of a light having to flash on and off every time you want to transfer data.) Researchers at the University of Washington have come up with a way to transfer data using almost no power at all. The system uses an effect known as “backscatter.” Objects in the path of RF emissions alter the characteristics of those waves, just as objects in the path of light beams can alter the light. The new device interferes with the transmission of passing radio waves in a way that can be detected and decoded by a receiver. Under ideal conditions, a Bluetooth transmission can carry about 330 feet (100 meters) though most devices are limited to 33 feet (10 meters). In contrast, the backscatter device has been demonstrated to work at a distance of 1.7 miles (2.8 kilometers). And it consumes about 1,000 times less power than a device with similar range.

The idea behind the system is similar to a signal mirror. By reflecting light from the sun in different patterns, a simple mirror can signal across great distances. Instead of the sun, the system uses a source of RF emissions. The researchers have developed a flexible skin patch and even a prototype “smart” contact lens that use this technology. In quantity, a backscatter microchip could be produced for as little as $0.10 per unit. The scientists have launched a business, Jeeva Wireless, to bring the technology to market and they hope to have product available in the first half of 2018. If they can bring their concept to fruition, it could revolutionize wearable Health Tech devices, as well as sensors for a wide range of consumer and business applications.