Paper-Based Sensor Detects Explosives

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The days of ye olde ink-jet printer only being able to print letters and images on paper are long gone. Today's printers can create just about anything you can imagine — everything from bikinis and skin, to car parts and scallop nuggets in the shape of a space ship.

So it comes as no surprise that some researchers from the Georgia Institute of Technology have created a prototype wireless sensor that can detect trace amounts of ammonia, often a key ingredient in explosives. Oh yeah, and they used a printer to do so.

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Using standard ink-jet technology, the wireless, ammonia-sensing prototype was printed on paper or a paper-like material. The sensing component utilizes carbon nanotubes which researchers say offer dramatically improved sensitivity over previous sensors. The lightweight antenna, which communicates this sensor information, was printed on photographic paper.

"This prototype represents a significant step toward producing an integrated wireless system for explosives detection,” the project's lead research scientist, Krishna Naishadham, said in a press release. “It incorporates a sensor and a communications device in a small, low-cost package that could operate almost anywhere.”

Naishadham said the device is an improvement on other hazardous gas sensors which are expensive, consume more power, require human intervention and often don't operate at ambient temperatures.

Manos Tentzeris, a professor at Georgia Tech’s School of Electrical and Computer Engineering, designed the ink-jet techniques used in the project. Tentzeris said the secret to successfully printing the device's components, circuits and antennas lies in using "inks" that contain silver nanoparticles in an emulsion that the printer can deposit at temperatures of around 212 degrees Fahrenheit.

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“Ink-jet printing is low-cost and convenient compared to other technologies such as wet etching,” Tentzeris said. “Using the proper inks, a printer can be used almost anywhere to produce custom circuits and components, replacing traditional clean-room approaches.”

But the paper-based, wireless prototype's foremost feature is that it offers "standoff detection", meaning that explosives can be detected from a distance without endangering human lives.

“We are focusing on providing standoff detection for those engaged in military or humanitarian missions and other hazardous situations,” Naishadham said. “We believe that it will be possible, and cost-effective, to deploy large numbers of these detectors on vehicles or robots throughout a military engagement zone.”

[Via NewsWise]

Image: Georgia Tech