These printable tags can convert everyday objects into smart devices

The metal tags named “LiveTag”, made from patterns of copper foil printed onto thin, flexible, paper-like substrates, are designed to only reflect specific signals within in the Wi-Fi frequency range.

The tags can be tacked onto plain objects that people touch and interact with every day, like water bottles, walls or doors. (Xinyu Zhang)

Researchers have developed printable metal tags that can be attached to everyday objects and turn them into 'smart' Internet of Things (IoT) devices by reflecting Wi-Fi signals.

The metal tags named "LiveTag", made from patterns of copper foil printed onto thin, flexible, paper-like substrates, are designed to only reflect specific signals within the WiFi frequency range.

"Our vision is to expand the IoT to go beyond just connecting smartphones, smartwatches and other high-end devices," said senior author Xinyu Zhang, Professor at the University of California San Diego.

"We're developing low-cost, battery-free, chipless, printable sensors that can include everyday objects as part of the IoT," Zhang added.

The tags can be tacked onto plain objects that people touch and interact with every day, like water bottles, walls or doors. These plain objects then essentially become smart, connected devices that can signal a Wi-Fi device whenever a user interacts with them.

The tags can also be fashioned into thin keypads or smart home control panels that can be used to remotely operate WiFi-connected speakers, smart lights and other IoT appliances.

As a proof of concept, the team used "LiveTag" to create a paper-thin music player controller complete with a play/pause button, next track button and sliding bar for tuning volume.

The buttons and sliding bar each consist of at least one metal tag so touching any of them sends signals to a WiFi device, suggests the study presented at the recent USENIX Symposium on Networked Systems Design and Implementation Conference.

The researchers also adapted "LiveTag" as a hydration monitor and attached it to a plastic water bottle and showed that it could be used to track a user's water intake by monitoring the water level in the bottle.

On a broader scope, the team envisions using "LiveTag" technology to track human interaction with everyday objects. For example, "LiveTag" could potentially be used as an inexpensive way to assess the recovery of patients who have suffered from stroke.