A major challenge for retailers, manufacturers, owners of lost keys, and just about everyone else who wants to keep track of things is that Bluetooth trackers require power and they’re not cheap. That means they need regular maintenance and they’re impractical for tracking low-cost items.

That’s about to change with Bluetooth stickers from Israeli startup Wiliot. The company showed off its battery-free Bluetooth stickers at the National Retail Federation’s Big Show in New York this week, and I got a chance to check them out in person.

The key innovation here is energy-harvesting tech that can draw enough power from ambient radio sources to power a Bluetooth device.

The loop of wire on the opposite side of the penny in this picture is an antenna that draws power from radio frequency energy that leaks from other devices (phones, wifi hotspots, etc.). The loop beside the penny is an antenna that transmits a Bluetooth signal. The device is opportunistic in that it transmits only when it has enough power to do so.

Another key innovation is an ARM processor that uses very little power. In the photo, it’s the black structure between the antennas. It also has encryption built in to protect the owner of something it’s attached to from access without their consent.

Wiliot’s Steve Statler told me that the sticker also packs in pressure and temperature sensors, as well as a sensor that can detect when the item it’s attached to is picked up.

Here’s a video showing how it works.

And here are just a few possible use cases that Statler mentioned to me:

  • Realtime inventory tracking and management in factories, distribution centers, and stores
  • Zero-click purchasing of store items for consumers (just put the thing in our cart and your card gets charged via store app on your phone when you walk out)
  • Security tracking for stores (no need to remove a bulky tag at checkout)
  • Medication tracking (did you pick up your pill bottle today?)
  • Unobtrusive glucose monitoring for diabetics (when integrated with a continuous glucose monitor)
  • Care guides for clothes that display on your phone so you don’t have to squint at a label
  • Automatic wash cycle selection when used with smart washing machines
  • “Wardrobing” applications that warn you when you’ve worn the same outfit too many times in a row
  • Micro-location for emergency services; tags in hotel room wallpaper, for example, can pinpoint the source of a 911 call

Wiliot plans to start selling its battery-free Bluetooth tags in 2020 for less than $1 each. The company, which launched in 2017, has taken in $50 million in investment from Amazon, Qualcomm, Samsung, Avery Dennison (whose booth Wiliot shared at NRF), and others. I think it’s safe to say we’ll soon start seeing these things just about everywhere.