Whiskers are a fantastic natural sensor that enables cats, fish, seals, and many other animals to detect not just direct contact but even air flow indicating an approaching object. In a fascinating example of biomimicry, University of Queensland engineer Pauline Pounds and her colleagues have developed tiny whisker sensors for drones. According to the researchers, the whiskers are well-suited for "navigating through dark, dusty, smoky, cramped spaces, or gusty, turbulent environments with micro-scale aircraft that cannot mount heavier sensors such as lidars." At IEEE Spectrum, Evan Ackerman writes:
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The whisker fibers themselves are easy to fabricate—they’re just blobs of ABS plastic that are heated up and then drawn out into long thin fibers like taffy. The length and thickness of the whiskers can be modulated by adjusting the temperature and draw speed. The ABS blob at the base of each whisker is glued to a 3D-printed load plate, which is in turn attached to a triangular arrangement of force pads (actually encapsulated MEMS barometers)...
It can detect forces as low as 3.33 micronewtons, meaning that the researchers had to be careful not to stand too close to the whiskers while making measurements since the force of their breathing would throw things off. This sensitivity allows the whiskers to detect the wave of air generated by objects moving towards them, perhaps not in time for the drone to actually stop, but certainly in time for it to take other steps to protect itself, like cutting power to its motors. The whiskers can also be used to measure fluid flow (a proxy for velocity through the air), and of course, at slow speeds they work as contact sensors.
Above is a micro-windmill that University of Texas Arlington researchers suggest could someday be used to charge mobile electronics if they were embedded en masse on the device's case. The MEMS (micro-electromechanical systems) are fabricated using recesses similar to the way integrated circuits are manufactured combined with origami-like self-assembly techniques.
“Imagine that they can be cheaply made on the surfaces of portable electronics,” says researcher Smitha Rao. "When the phone is out of battery power, all you need to do is to put on the sleeve, wave the phone in the air for a few minutes and you can use the phone again.”
She adds that eventually, flat panels coated with the windmills could be mounted to buildings to harvest energy for sensor networks, wireless communications, lighting or other purposes.
Check out the video below of the windmills in action! (via Wired) Read the rest
German start-up Nanoscribe is commercialized a 3D "micro printer" that uses a near-infrared laser to print tiny structures with features as small as 30 nanometers. (A human hair is roughly 50,000 - 100,000 nanometers wide.) The device uses an infra-red laser beam moving in three dimensions to solidify a light-sensitive material into the desired shape. The additive manufacturing system, much faster than existing technology, could be used to "print" the components of medical devices, electromechanical systems, and, er, robot models that would fit on the head of a pin.
"Micro 3-D Printer Creates Tiny Structures in Seconds" (Technology Review, thanks Anthony Townsend!) Read the rest
[Video Link]Excellent video by Bill Hammock that looks at the accelerometer in a mobile phone, and how it's made.
Bill takes apart a smartphone and explains how its accelerometer works. He also shares the essential idea underlying the MEMS production of these devices.This video is based on a chapter from the EngineerGuy team's latest book Eight Amazing Engineering Stories.
(Via Cult of Mac) Read the rest