There is energy in the air all around us at all times. This isn't a pseudo-mystical statement either; the sheer amount of power from radio and television waves in the air is a massive, untapped resource. At least it was, until Washington University hit on a way to use it that's referred to as ambient backscatter.

What is Ambient Backscatter, and How Does it Work?

The idea of ambient backscatter is that it should be possible to use existing transmission waves to power battery-less devices in such a way that they can still perform simple tasks. The theory was that these devices could communicate with one another, act as sensors, and even send simple text messages. There would be no requirement of additional power, and it would make use of an environmental factor that's already filling the area. In fact these devices would work anywhere there's a number of wavelengths filling the air, whether they're for cell phones, Internet, television, or some other application entirely.

The devices are designed so that, rather than using an on-board source of power, they can draw power from the electromagnetic waves in the area. Scientists tested the range from as far as a few feet, to six and a half miles using these devices that rode the radio waves to get their messages sent. Further testing is still in the works, but the initial tests show some serious potential.

What are the Potential Benefits of Ambient Backscatter?

This unusual development has caught hold of the scientific imagination, and the potential for these devices is nearly limitless. For instance, they could be put on a bridge to monitor the integrity of the concrete. When a hairline fracture occurs, the sensor beams a message back on the already existing wavelengths. This requires no changing out, no battery upkeep, no power source; it's just a constant, never-sleeping guardian that keeps watch. The same sensors could be used to watch for fires, for security networks, and a dozen other applications. Simply install, and leave it unless something breaks the sensor so completely that it isn't physically intact anymore.

These devices could, in theory, also be worked into existing electronics that do use batteries so that even when the charge is completely drained some basic forms of communication are still possible. This would also allow for things like text messages to be composed and sent without actually putting a drain on the battery, making phones last longer on a single charge simply by virtue of using less power than they might otherwise do.

A Green Future 

There's no use in letting anything go to waste; not even ambient cell phone energy. So if it's possible to send a text, or to monitor a secure location, without spending one iota of power, then who wouldn't take advantage of that? In fact, given the potential these devices offer, it's possible that miniaturized devices will become even more popular. Miniature computers that work free of battery packs, or only on tiny watch batteries, might become the next generation of technology when existing wavelengths can provide the brunt of the heavy lifting needed.

This guest post was provided by Eduardo Dieguez, professional blogger for An avid computer enthusiast, Eduardo spends countless hours tinkering with electronics both new and old.

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