Sensors play a crucial role in the Internet of Things, but there's one glaring limitation: they need a battery or some other conspicuous power source to run. Soon, however, they might only have to pluck energy from the air. Wiliot has shown off a Bluetooth sensor tag that gathers energy from ambient radio frequencies, whether it's Bluetooth, cellular or WiFi. All the ARM-based chip needs is a basic antenna printed on paper or plastic -- after that, it can transmit info like weight and temperature without any kind of battery involved.
The battery-free approach could lead to sticker-like tags on products where they weren't always an option before. Clothing could warn you when you're about to ruin your white clothing in the wash, while packaging could track products from their origins to your door. And since there's only minimal gear involved, the tags shouldn't add much to the cost.
The tags aren't poised to arrive until 2020. They'll have some help getting there, though. Wiliot just finished a round of funding that includes help from investment arms at Amazon and Samsung. Tech giants want the tech to succeed, and you might just see these tags in widespread use soon after they're ready.