Is the ultra-low-power sensor the future of tracking?

While companies continue to dither about whether to jump in the RFID game to enhance their supply chain tracking, science marches on. At a recent conference at the Massachusetts Institute of Technology (MIT), several scientists offered a preview of the next generation of radio-frequency identification technology—ultra-low-power radio sensing devices.

This new type of RFID tag consists of a tiny bundle of electronic components that include control circuits, a battery, and a radio receiver that weighs about one gram. The tiny tag's energy requirements are correspondingly minuscule: The device itself consumes less than one milliwatt of power.

The sensing device was originally developed as part of a federally funded project to create a tracking system small and powerful enough to control the flight of an insect. In tests, the unit was attached to a moth, and scientists sent flight control commands to the unit's receiver in bursts using ultra-wide-band transmissions.

The same device used to track insects could potentially be used to track cargo, according to a recent white paper from MIT, Transforming the Future of Supply Chains Through Disruptive Technology, Ultra-Low-Power Sensing. By way of example, the publication notes that these ultra low-power devices could be attached to a pallet, allowing the unit's whereabouts to be monitored without the need for handheld or stationary readers. Instead, data could be transmitted to the Internet by various means, including using a smart phone as a local relay.

That would be a huge advantage over existing systems, according to the white paper. The communications network for supply chains has historically been limited in scope by contraints on sensing power and the ability to collect data from sensors, according to Jim Rice, deputy director of MIT's Center for Transportation & Logistics. If you remove these constraints, he says, all kinds of new possibilities open up. On top of that, eliminating this equipment would reduce infrastructure costs and remove a common source of data transmission delays.

As for what led the MIT scientists to focus on freight tracking as a potential use for the technology, it's all about the power requirements, says the project's leader, MIT Professor Anantha Chandrakasan. For tracking purposes, shippers want regular—but not constant—updates on their freight's whereabouts. Therefore, the rate at which shipment-status data needs to be collected and transmitted is relatively low, and the power requirements relatively modest. To further reduce power requirements, the sensors could be engineered to transmit data in bursts and then go to sleep between transmissions.

In addition to freight tracking, the MIT researchers envision several other supply chain-related applications for the technology. For instance, they note that the sensing devices could be used for monitoring inventory status at retail stores to help prevent stock-outs. And as more companies turn to business analytics to monitor supply chain performance (see "Should analytics be part of your routine," TechWatch, September 2011), these devices could gather the detailed product-tracking data needed for analysis.

Although these sensing devices hold a lot of promise from a technical point of view, they'll have to clear a few hurdles before they can gain widespread market acceptance. One is the very same challenge that has historically bedeviled RFID: cost. Still, the MIT scientists remain confident that this challenge can be overcome, arguing that for mass-market uses, the price could be brought down to a few cents per unit.

All in all, the researchers seem bullish on the technology, which they say "has the potential to bring about structural changes in supply chains that spawn new processes and alter the economics of moving goods efficiently." Or as Chandrakasan observes in the white paper, advances in electronics will usher in "a lot of exciting opportunities" for future supply chain applications.