January R&D Round UpJanuary 13, 2012 By: Melanie Martella, Sensors
Welcome to 2012! As we start the new year, how about some intriguing research breakthroughs? This month we've got a sensitive airflow sensor that takes design pointers from crickets, microneedle sensors for real-time medical diagnostics, and wireless probes to spot termites before they destroy your house.
A Novel Airflow Sensor
Crickets have a neat trick up their exoskeleton; tiny hairs on their abdomen act as an early warning system, allowing them to spot approaching enemies and precisely locate them. Researchers at the University of Twente in the Netherlands have mimicked the construction of these hairs to create a sensor that is sensitive to airflows with a specific frequency. The tiny tapered polymer 'hair' is attached to a flexibly-suspended base and as it moves it causes a measurable capacitance change. That's neat, right? But it gets even neater! It turns out that if the hair is more flexible when exposed to airflows of the desired frequency, it becomes far more sensitive. The researchers, led by Harmen Droogendijk, discovered that by varying the alternating voltage they could alter the spring stiffness of the hairs and thus increase their sensitivity to certain frequencies. To read more, and see some lovely pictures of the devices, read "Synthetic cricket pricks up its 'ears.'"
When it comes to medical diagnostics, real-time information can be a lot more valuable than taking a sample and waiting a day for results. Because body chemistry is such a complex beast involving multiple interlocked feedback loops, the ability to measure, in real-time, what's happening with someone's body chemistry is immensely attractive. Researchers from North Carolina State University, Sandia National Laboratories, and the University of California, San Diego have developed microneedle sensor arrays that accomplish just this, and enable these real-time measurements over extended periods. Microneedles themselves aren't new; what makes this project so interesting is that, instead of filling the microneedles with vaccines or other controlled-release drugs, these microneedles contain electrochemical sensors. The current array, built as a proof-of-concept, includes sensors for pH, glucose, and lactate and is designed for studying metabolic acidosis, but as the original article points out, the types of sensors could be changed to target different types of monitoring.
Listening for Termites
Termites may be good news for the ecosystem as a whole, but they are very bad news for home owners. Current detection methods rely on spotting the pellets they leave behind or finding the telltale structures that they build in walls, by which time you already have the infestation and they've already done damage. What if you could spot a termite incursion at an earlier stage? That's the idea behind the WiSPr wireless smart probe network for termite detection, described in the PhysOrg.com article, "Smart probe detects termites by 'hearing' them eat". Researchers at Australia's Edith Cowan University have created a smart probe that couples a tiny acoustic sensor with wireless communications. Placing the probes around a structure or in the ground creates a sensor network to 'listen' for the sound of termites munching and then alert pest control firms or maintenance personnel that termites are present, along with the GPS location. By providing automated early detection of termite infestations, WiSPr won't just protect homes and other buildings; it could be used to protect other wooden structures, including bridges and phone poles. I wonder if it'd work for carpenter ants?
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