Camera Uses Algorithms Instead Of Lenses

September 15, 2018 by Al Williams 21 Comments

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 of field of about 10 mm. This may seem like a solution that needs a problem, but think about the applications where a camera could see through a windshield or a pair of glasses without having a conventional camera in the way.

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Motorized Stage Finesses The Microscopic World

May 19, 2018 by Dan Maloney 12 Comments

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 on a budget. Granted, not too many people are in [fabiorinaldus]’ position of having a swell microscope like the Olympus IX50, and those that do probably work for an outfit that can afford all the bells and whistles. But this home-brew stage ticks off all the boxes on design and execution. The slide is moved across the stage in two dimensions with small NEMA-8 steppers and microstepping controllers connected to two linear drives that are almost completely 3D-printed. The final resolution on the drives is an insane 0.000027344 mm. An Arduino lives in the custom-built control box and a control pad with joystick, buttons, and an OLED display allow the stage to return to set positions of interest. It’s really quite a build.

We’ve featured a lot of microscope hacks before, most of them concerning the reflective inspection scopes we all seem to covet for SMD work. But that doesn’t mean we haven’t shown love for optical scopes before, and electron microscopes have popped up a time or two as well.

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First Light: The Story Of The Laser

January 8, 2018 by Dan Maloney 36 Comments

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 of observation, perseverance, and the importance of keeping good notes.

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Arduino And Encoder Form Precision Jig For Cutting And Drilling

June 4, 2017 by Dan Maloney 24 Comments

“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 incorporating such compliant materials as particle board and scraps of plumber’s strapping. Looking to build a more robust machine, he finds himself in need of parts of consistent and accurate lengths, so he built this jig. A sled of particle board and a fence of angle aluminum position the square tube stock, and a roller with a paper encoder wheel bears on the tube under spring pressure. By counting pulses from the optical sensors, he’s able to precisely position the tube in the jig for cutting and drilling operations. See it in action in the video after the break.

If you’ve been following [HomoFaciens], you’ll no doubt see where he’s been going — build a low-end tool, use that to build a better one, and so on. We’re excited to see him moving into more robust materials, but we’ll miss the cardboard and paperclip builds.

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Apollo: The Alignment Optical Telescope

September 6, 2016 by Gerrit Coetzee 17 Comments

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. It was used to align the craft to the stars. NASA used stars as the fixed reference points for the coordinate system used to locate objects in space. But how was this accomplished with great precision?

The alignment optical telescope did this by measuring two unknowns needed by the guidance computer. The astronaut would find the first value by pointing the telescope in the general area necessary to establish a reading, then rotate the first reticle (a horizontal line) on the telescope until it touched the correct star. A ring assembly was then adjusted, moving an Archimedes spiral etched onto the viewfinder. When the spiral touches the star you can read the second value, established by how far the ring has been rotated.

If you’ve ever seen the Lunar Module in person, your first impression might be to giggle a bit at how crude it is. The truth is that much of that crudeness was hard fought to achieve. They needed the simplest, lightest, and most reliable assembly the world had ever constructed. As [Bill Hammack] states at the end of the video, breaking the complicated tool usually used into two simple dials is an amazing engineering achievement.

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Big Brother And Others Are Watching Your Car

August 31, 2016 by Bryan Cockfield 63 Comments

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 of the gear was set up on an overpass and the camera was aimed at cars coming around a corner of a highway. As soon as the cars enter the frame, the USB camera feeds the information to a laptop running openALPR which is able to process and record license plate data.

The build is pretty impressive, but [Saulius] notes that it isn’t the ideal setup for processing a large amount of information at once because of the demands made on the laptop. With this equipment, monitoring a parking lot would be a more feasible situation. Still, with even this level of capability available to anyone with the cash, imagine what someone could do with the resources of a national government. They might even have long distance laser night vision!

Single Molecule Detects Light

June 23, 2016 by Al Williams 12 Comments

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 University in Beijing determined that placing some buffering material between the molecule and the electrodes would reduce the interference enough to maintain correct operation. What’s more the switches remain operable for a year, which is unusually long for this kind of construct.

Using chemical vapor deposition and electron beam lithography, the team produced over 40 working single molecule switches. These devices could be useful in optical computing and other applications. Future work will include developing multilevel switches comprised of multiple molecules.

If you want something more macroscopic, you might try using an LED to sense light. A switch is fine, but sometimes you want to generate a signal.