University of Washington engineers have introduced a new way of communicating that allows devices like brain implants, contact lenses, credit cards and smaller wearable electronics to talk to everyday devices such as smartphones and watches.

This new "interscatter communication" works by converting Bluetooth signals into Wi-Fi transmissions over the air. Using only reflections, an interscatter device such as a smart contact lens converts Bluetooth signals from a smartwatch, for example, into Wi-Fi transmissions that can be picked up by a smartphone.

"Wireless connectivity for implanted devices can transform how we manage chronic diseases," said co-author Vikram Iyer, a UW electrical engineering doctoral student. "For example, a contact lens could monitor a diabetics blood sugar level in tears and send notifications to the phone when the blood sugar level goes down."

Due to their size and location within the body, these smart contact lenses are too constrained by power demands to send data using conventional wireless transmissions. That means they so far have not been able to send data using Wi-Fi to smartphones and other mobile devices.

Those same requirements also limit emerging technologies such as brain implants that treat Parkinson’s disease, stimulate organs and may one day even reanimate limbs.

EETI Interscatter 01 Figure 1: “Interscatter” communication generates low-power Wi-Fi transmissions using every day mobile devices. In one example, Bluetooth signals from a smartwatch (left) transmit data from a neural device that can be implanted in a patient’s brain (right) to a smartphone via Wi-FI.(Source: Mark Stone/University of Washington)

The team of UW electrical engineers and computer scientists has demonstrated for the first time that these types of power-limited devices can "talk" to others using standard Wi-Fi communication. Their system requires no specialised equipment, relying solely on mobile devices commonly found with users to generate Wi-Fi signals using 10,000 times less energy than conventional methods.

"Instead of generating Wi-Fi signals on your own, our technology creates Wi-Fi by using Bluetooth transmissions from nearby mobile devices such as smartwatches," said co-author Vamsi Talla, a recent UW doctoral graduate in electrical engineering who is now a research associate in the Department of Computer Science & Engineering.

The team's process relies on a communication technique called backscatter, which allows devices to exchange information simply by reflecting existing signals. Because the new technique enables inter-technology communication by using Bluetooth signals to create Wi-Fi transmissions, the team calls it "interscattering."

Next: How interscatter tech eliminates backscattering by-products