Category Archives: optical

Seeing a Webcam’s PCBs in a Whole Different Light

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When it comes to inspection of printed circuits, most of us rely on the Mark I eyeball to see how we did with the soldering iron or reflow oven. And even when we need the help of some kind of microscope, our inspections are still firmly in the visible part of the electromagnetic spectrum. Pushing the frequency up a few orders of magnitude and inspecting PCBs with X-rays is a thing, though, and can reveal so much more than what the eye can see.

Unlike most of us, [Tom Anderson] has access to X-ray inspection equipment in the course of …read more

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Camera Uses Algorithms Instead of Lenses

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A normal camera uses a lens to bend light so that it hits a sensor. A pinhole camera doesn’t have a lens, but the tiny hole serves the same function. Now two researchers from the University of Utah. have used software to recreate images from scattered unfocused light. The quality isn’t great, but there’s no lens — not even a pinhole — involved. You can see a video, below.

The camera has a sensor on the edge of a piece of a transparent window. The images could resolve .1 line-pairs/mm at a distance of 150 mm and had a depth …read more

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Motorized Stage Finesses the Microscopic World

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No matter how fine your fine motor skills may be, it’s really hard to manipulate anything on the stage of a microscope with any kind of accuracy. One jitter or caffeine-induced tremor means the feature of interest on the sample you’re looking at shoots off out of the field of view, and getting back to where you were is a tedious matter of trial and error.

Mechanical help on the microscope stage is nice, and electromechanical help is even better, but a DIY fully motorized microscope stage with complete motion control is the way to go for the serious microscopist …read more

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First Light: The Story of the Laser

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Lasers are such a fundamental piece of technology today that we hardly notice them. So cheap that they can be given away as toys and so versatile that they make everything from DVD players to corneal surgery a reality, lasers are one of the building blocks of the modern world. Yet lasers were once the exclusive province of physicists, laboring over expansive and expensive experimental setups that seemed more the stuff of science fiction than workhouse tool of communications and so many other fields. The laser has been wildly successful, and the story of its development is an intriguing tale …read more

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Malware Steals Data From Air-Gapped Network via Security Cameras

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Proof-of-concept malware called aIR-Jumper can be used to bypass air-gapped network protections and send data in and out of network. Continue reading Malware Steals Data From Air-Gapped Network via Security Cameras→

Arduino and Encoder form Precision Jig for Cutting and Drilling

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“Measure twice, cut once” is great advice in every aspect of fabrication, but perhaps nowhere is it more important than when building a CNC machine. When precision is the name of the game, you need measuring tools that will give you repeatable results and preferably won’t cost a fortune. That’s the idea behind this Arduino-based measuring jig for fabricating parts for a CNC build.

When it comes to building on the cheap, nobody holds a candle to [HomoFaciens]. We’ve seen his garbage can CNC build and encoders from e-waste and tin cans, all of which gave surprisingly good results despite …read more

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Apollo: The Alignment Optical Telescope

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The Apollo program is a constant reminder that we just don’t need so much to get the job done. Sure it’s easier with today’s tools, but hard work can do it too. [Bill Hammack] elaborates on one such piece of engineering: The Alignment Optical Telescope.

The telescope was used to find the position of the Lunar Module in space so that its guidance computer could do the calculations needed to bring the module home. It does this using techniques that we’ve been using for centuries on land and still use today in space; although now it’s done with computer vision. …read more

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Big Brother and Others Are Watching Your Car

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We are all (hopefully) aware that we can be watched while we’re online. Our clicks are all trackable to some extent, whether it’s our country’s government or an advertiser. What isn’t as obvious, though, is that it’s just as easy to track our movements in real life. [Saulius] was able to prove this concept by using optical character recognition to track the license plate numbers of passing cars half a kilometer away.

To achieve such long distances (and still have clear and reliable data to work with) [Saulius] paired a 70-300 mm telephoto lens with a compact USB camera. All …read more

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Single Molecule Detects Light

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Everything is getting smaller all the time. Computers used to take rooms, then desks, and now they fit in your pocket or on your wrist. Researchers that investigate light sensors have known that individual diarylethene molecules can exist in two states: one where it conducts electricity and one where it doesn’t. A visible photon causes the molecule to be electrically open and ultraviolet causes it to close. But there’s a problem.

Placing electrodes on the molecule interferes with the process. Depending on the kind of electrode, the switch will get stuck in the on or off position. Researchers at Peking …read more

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Graphene Optical Boom Emits Light with No Diode

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When a supersonic aircraft goes faster than the speed of sound, it produces a shockwave or sonic boom. MIT researchers have found a similar optical effect in graphene that causes an optical boom and could provide a new way to convert electricity into light.

The light emission occurs due to two odd properties of graphene: first, light gets trapped on the surface of graphene, effectively slowing it down. In addition, electrons pass through at very high speeds. Interestingly, the speeds are nearly the same–that is, electrons and trapped light travel at almost the same speed. The researchers found a way …read more

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