Despite the growing use of wireless radio frequency ID (RFID) tags, lost inventory still costs warehouses billions of dollars every year. Researchers from the Massachusetts Institute of Technology (MIT) have developed an aerial way of supplementing the RFID technology: small, safe drones.

At several meters, the unmanned vehicles read the tags located within a warehouse environment. The airborne circuit detects a box’s RFID tag, and the drone can catalog and locate items as it flies up and down the aisles.

The drones identify tag locations with an average error of about 19 centimeters.

Could the system be used in large warehouses to more efficiently find items and meet customer requests? Fadel Adib, Assistant Professor of Media Arts and Sciences, whose group at the MIT Media Lab developed the new ‘RFly’ system, spoke with Tech Briefs.

Tech Briefs: What are the drawbacks of RFID technology?

Prof. Fadel Adib: Due to their battery-free nature, RFIDs are crippled by their communication range: tens of centimeters to a few meters. The range becomes lower if an RFID is, say, under a stack of shirts. As a result, even though RFIDs are widely adopted, companies like Walmart still lose billions of dollars every year because of faulty inventory control and misplaced items, since they are unable to read the RFIDs due to this limited range.

Tech Briefs: How does your RFly approach address those RFID drawbacks?

MIT researchers have developed a system that enables small, safe, aerial drones to read RFID tags at a distance of several meters. (Credit: MIT)

Adib: RFly overcomes this challenge and enables cataloging and locating battery-free RFIDs over a wide area. It is a drone-based technology that can seamlessly integrate with an existing RFID infrastructure and extend the coverage area of every reader by 100x.

Tech Briefs: What is the technology used? How is the drone equipped?

Adib: We built a relay that sits on the drone and acts as a repeater. The relay, with a built-in RFID antenna, can receive a signal from the reader (a wireless device that queries RFIDs), then use the power from that signal, as well as the drone's built-in battery, to forward an interrogating signal that is received by passive RFID tags within its vicinity. The tags respond, and the relay captures their IDs and forwards that information to the reader. The reader software approximates each tag's location based on the angle at which its ID is received as the drone is moving, using algorithms to determine where the tag is situated, according to the drone's location and the angle of RF response.

Tech Briefs: Take me through the process. How are drones used to provide continuous monitoring?

Adib: To scan a warehouse, a drone operator dispatches a small, inexpensive, and safe drone which flies throughout a warehouse, cataloging and localizing all the RFIDs in a warehouse. This MIT video shows how the system operates.

Tech Briefs: Why is this approach so valuable?

Adib: The applications are vast, and they range from doing remote inventory control in an entire warehouse to allowing people to find missing items at home. Imagine a future where each of us has a small miniature drone, and we dispatch the drone to fetch our keys, wallets, or glasses when we can't find them at home. Even today, this technology can solve multi-billion-dollar challenges facing many industries in warehouse inventory control. Consider that the smallest Walmart warehouse is larger than 17 football fields — an easy place for things to get lost. Our drones can fly around the warehouse cataloging items and finding misplaced ones.

Tech Briefs: Where did you test this, and what were your biggest challenges in getting this system to work effectively?

Adib: We tested the technology in MIT’s Media Lab building. We also further tested the technology at a furniture retailer warehouse, in the greater Boston area, for the stability and safety of the technology. The biggest challenge we faced is that today’s small, safe drones have a very limited payload, so we needed to ensure that the technology is low-weight enough to be carried by drones that are safe to fly around people.

Tech Briefs: Do you see this becoming a mainstream logistics technology?

Adib: We are working on developing and testing the technology more, and hope that in the near future, it can become mainstream in logistics given how much it can improve efficiency.

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