Printable metal tags have been developed that can turn an everyday item into a smart device. The metal tags have been named LiveTag. LiveTags are made of copper-foil patterns that are printed between thin, flexible, paper-like substrates that reflect Wi-Fi signals.
Printed thin, flexible LiveTag tags in comparison with a piece of photo paper (far left). (Source: Xinyu Zhang et al.)
LiveTag reflects radio signals from a Wi-Fi router. When the user touches a LiveTag, the press disturbs the reflected Wi-Fi signals and the receiver (like a smartphone) senses the disruption and follows through with the required action. LiveTag can be attached to pretty much any plain object that isn’t metal, like plastic water bottles, doors and more.
"Our vision is to expand the Internet of Things to go beyond just connecting smartphones, smartwatches and other high-end devices," said senior author Xinyu Zhang, a professor of electrical and computer engineering at the UC San Diego Jacobs School of Engineering and member of the Center for Wireless Communications at UC San Diego. "We're developing low-cost, battery-free, chipless, printable sensors that can include everyday objects as part of the Internet of Things."
LiveTags are designed to reflect specific signals within the range of a Wi-Fi router. A small change in the material could allow the tags to reflect Bluetooth or LTE signals. LiveTags don’t have batteries, silicon chips or any discrete electronics. This means LiveTags doesn’t have any circuits that will need to be fixed or batteries that need to be changed.
To test the new device, LiveTag was used to create a paper-thin music-player controller with play, pause and next buttons and a sliding bar for volume. Each button required at least one metal tag. One day the researchers hope that it could be attached to a sofa, wall, couch and more to create various passive household controllers.
LiveTag was also developed as a hydration tracker. Researchers attached LiveTag to a plastic water bottle where the tag tracked the user’s water intake by monitoring the water level in the plastic water bottle.
The team hopes that LiveTag could be used on a larger level to track how people interact with everyday objects. For example, they believe that LiveTag could be an inexpensive way to track how a stroke patient is recovering at home.
"When patients return home, they could use this technology to provide data on their motor activity based on how they interact with everyday objects at home--whether they are opening or closing doors in a normal way, or if they are able to pick up bottles of water, for example. The amount, intensity and frequency of their activities could be logged and sent to their doctors to evaluate their recovery," said Zhang. "And this can all be done in the comfort of their own homes rather than having to keep going back to the clinic for frequent motor activity testing.”
LiveTag could even be used in retail stores to track how customers are interacting with products and which products are receiving more interest.
Currently, LiveTag doesn’t work beyond 1 m from the Wi-Fi receiver. In the future, researchers hope to improve this as well as the device’s sensitivity.
To learn more about Live Tag, access the paper on the University of Wisconsin website.