• Tiny sensors that measure amplitude are big step

    Vijay Kumar / Purdue University

    Researchers have learned how to improve the performance of sensors that use tiny vibrating "microcantilevers," like the one pictured here, to detect chemical and biological agents for applications from national security to food processing.

    By John Roach, Contributing Writer, NBC News

    Anyone who watched the recent X-Games coverage heard commentators obsess about "amplitude" — how high snowboarders such as Shaun White soar above the lip of the superpipe to perform aerial tricks.

    Scientists more concerned with using vibrating sensors to detect harmful chemicals in the air we breathe and food we eat than White's frontside double cork 1260 share the love for amplitude.

    In their case, they've found that a change in the amplitude of a tiny sensor's vibration is a reliable indication that a chemical of interest has glommed onto it. 

    Sensors that measure shifts in frequency — how often a vibrating motion repeats itself — when a chemical of interest sticks to it have been around for a while, noted Jeffrey Rhoads, a mechanical engineer at Purdue University in West Lafayette, Indiana.

    "But when the devices get smaller, that can be harder to do due to noise," he explained to me Tuesday. That is, at small scales, scientists have a hard time detecting changes in frequency that are due to the chemical of interest from changes because of other factors.

    To get around this, Rhoads and colleagues found that they can measure changes in amplitude instead. The breakthrough, he said, could lead to applications everywhere from food safety and national security to, eventually, biomedical research.

    Proof-of-concept experiments showed that change in amplitude was a more reliable way to detect the presence of small quantities of methanol gas than the frequency approach.

    Applied to other gases this could be useful, for example, when attempting to determine the safety of food, Rhoads said. "If there's a little bit of something bad, the whole thing is shot."

    Looking to the future, the team hopes to apply these sensors to things like detecting the concentration of certain cells in a person's blood, for example.

    To get there will require improvements to measure not just the presence of a chemical, but also its concentration. Doing so will require better understanding of the chemistry of the chemicals of interest.

    Findings are detailed a paper appearing online this week in the Journal of Microelectromechancial Systems.

    More on sensor technology:

    John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more of our Future of Technology series, watch the featured video below.

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  • Printable sensors detect bombs

    Georgia Tech / Gary Meek

    Krishna Naishadham, left, and Xiaojuan (Judy) Song display two types of wireless ammonia-sensing prototype devices.

    By John Roach, Contributing Writer, NBC News

    If there's a suspicious package on the doorstep and you want to know if it’s a bomb, you may soon be able to print out a sensor that can do just that.

    The ability to make bomb-detecting sensors with inkjet printer technology could also benefit soldiers on the lookout for roadside bombs and aid agencies working in war-torn countries.

    The technology to do this is under development at the Georgia Institute of Technology, where researchers have created a sensor that communicates its findings wirelessly.

    The manufacturing process requires an inkjet printer that has a "much finer resolution than the standard household printer and it uses special inks," Krishna Naishadham, a research engineer who is leading the project, told me Tuesday.

    The ink for the sensor circuitry is a commercially available emulsion of silver nanoparticles, and the ink for the sensing element consists of bundled carbon nanotubes that have been mixed in a solution of water.

    The team uses a process called sonification which helps this ink achieve an optimal viscosity and homogeneity, allowing it to be easily deposited on a piece of photographic paper.

    The nanotubes — each about one billionth of a meter in diameter, or 1/50,000th the width of a human hair — are coated with a conductive polymer that attracts ammonia, a key ingredient found in many explosives.

    The sensor has been designed to detect trace amounts of ammonia — as low as five parts per million, but since ammonia is also found in non-explosive devices such as fertilizer and urine, more work is needed before the technology is ready for commercialization.

    "In order to develop this fully into an explosive sensor, we need to improve the sensitivity, we need to filter out other materials that might interfere with what we are trying detect — detecting ammonium by itself is not sufficient," Naishadham said.

    More research is also needed to seamlessly integrate a power supply for the sensors. Potential technologies include thin-film batteries, solar cells and energy-harvesting techniques.

    But with two years of research and another year to commercialize, Naishadham said these sensors could be available for as little as tens of dollars each for use in industrial settings, and perhaps a few hundred dollars when tuned up for military applications.

    [Via: Gizmag and Georgia Tech]

    More on bomb-detection technology:

    A presentation on this sensing technology was given this July at the IEEE Antennas and Propagation Symposium in Spokane, Wash., by Hoseon Lee, a Ph.D. student at Georgia Tech.

    John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more of our Future of Technology series, watch the featured video below.

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