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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The Pros And Cons Of Microcontrollers For Boost Converters

May 17, 2018 by Dan Maloney 37 Comments

It never fails — we post a somewhat simple project using a microcontroller and someone points out that it could have been accomplished better with a 555 timer or discrete transistors or even a couple of vacuum tubes. We welcome the critiques, of course; after all, thoughtful feedback is the point of the comment section. Sometimes the anti-Arduino crowd has a point, but as [Great Scott!] demonstrates with this microcontroller-less boost converter, other times it just makes sense to code your way out of a problem.

Built mainly as a comeback to naysayers on his original boost-converter circuit, which relied on an ATtiny85, [Great Scott!] had to go to considerable lengths to recreate what he did with ease using a microcontroller. He started with a quick demo using a MOSFET driver and a PWM signal from a function generator, which does the job of boosting the voltage, but lacks the feedback needed to control for varying loads.

Ironically relying on a block diagram for a commercial boost controller chip, which is probably the “right” tool for the job he put together the final circuit from a largish handful of components. Two op amps form the oscillator, another is used as a differential amp to monitor the output voltage, and the last one is a used as a comparator to create the PWM signal to control the MOSFET. It works, to be sure, but at the cost of a lot of effort, expense, and perf board real estate. What’s worse, there’s no simple path to adding functionality, like there would be for a microcontroller-based design.

Of course there are circuits where microcontrollers make no sense, but [Great Scott!] makes a good case for boost converters not being one of them if you insist on DIYing. If you’re behind on the basics of DC-DC converters, fear not — we’ve covered that before.

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A Vacuum Tube And Barbecue Lighter X-Ray Generator

May 12, 2018 by Dan Maloney 58 Comments

A certain subset of readers will remember a time when common knowledge held that sitting too close to the TV put you in mortal peril. We were warned to stay at least six feet back to avoid the X-rays supposedly pouring forth from the screen. Nobody but our moms believed it, so there we sat, transfixed and mere inches from the Radiation King, working on our tans as we caught up on the latest cartoons. We all grew up mostly OK, so it must have been a hoax.

Or was it? It turns out that getting X-rays from vacuum tubes is possible, at least if this barbecue lighter turned X-ray machine is legit. [GH] built it after playing with some 6J1 rectifier tubes and a 20-kV power supply yanked from an old TV, specifically to generate X-rays. It turned out that applying current between the filament and the plate made a Geiger counter click, so to simplify the build, the big power supply was replaced with the piezoelectric guts from a lighter. That worked too, but not for long — the tube was acting as a capacitor, storing up charge each time the trigger on the lighter was pulled, eventually discharging through and destroying the crystal. A high-voltage diode from a microwave oven in series with the crystal as a snubber fixed the problem, and now X-rays are as easy as lighting a grill.

We have to say we’re a wee bit skeptical here, and would love to see a video of a test. But the principle is sound, and if it works it’d be a great way to test all those homebrew Geiger counters we’ve featured, like this tiny battery-powered one, or this one based on the venerable 555 timer chip.

Alexa, Attack Intruders

May 8, 2018 by Richard Baguley 3 Comments

If our doom at the hands of our robot overlords is coming, I for one welcome the chance to get a preview of how they might go about it. That’s the idea behind Project Icarus, an Alexa-enabled face-tracking Nerf turret. Designed by [Nick Engmann], this impressive (or terrifying) project is built around a Nerf Vulcan, a foam dart firing machine gun mounted on a panning turret that is hidden behind a drop-down cabinet door. This is connected to a Pi Zero equipped with a Pi camera. The Zero is running OpenCV and Google Firebase, which connects it with Amazon’s Alexa service.

It works like this: you say “Alexa, open Project Icarus”. Through the Alexa skill that [Nick] created, this connects to the Pi and starts the system. If you then say “Alexa, activate alpha”, it triggers a relay to open the cabinet and the Nerf gun starts panning around, while the camera mounted on the top of it searches for faces. The command “Alexa, activate beta” triggers the Nerf to open fire.

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Hurricane Simulator Buoys Research

May 6, 2018 by Kristina Panos 1 Comment

They say an ounce of prevention is worth a pound of cure. In this case, 38,000 gallons of seawater is worth an un-quantifiable amount of knowledge about hurricanes. At the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, [Brian Haus] and his colleagues study hurricanes using a simulator–an enclosed glass tank about the size of a lap-swimming pool. With the flip of a switch, a 1700 hp fan can create winds up to 200 miles per hour—stronger than a baseline category 5 hurricane.

Although there’s currently no cure for hurricanes, understanding how they work goes a long way in forecasting their intensity. Scientists know that hurricanes are fueled by the ocean’s warmth, but there’s still plenty of mystery to them. By studying what happens where the wind meets the water, they think they’ll figure out how surface factors like sea spray and bubbles affect a storm’s intensity and drag coefficient. Surf the break to catch the wave tank in action.

Until there’s a cure for hurricanes, we’ll just have to live with them and engineer our structures to withstand them.

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Step The Halbach From My Magnets

May 4, 2018 by Brian McEvoy 5 Comments

[Klaus Halbach] gets his name attached to these clever arrangements of permanent magnets but the effect was discovered by [John C. Mallinson]. Mallinson array sounds good too, but what’s in a name? A Halbach array consists of permanent magnets with their poles rotated relative to each other. Depending on how they’re rotated, you can create some useful patterns in the overall magnetic field.

Over at the K&J Magnetics blog, they dig into the effects and power of these arrays in the linear form and the circular form. The Halbach effect may not be a common topic over dinner, but the arrays are appearing in some of the best tech including maglev trains, hoverboards (that don’t ride on rubber wheels), and the particle accelerators they were designed for.

Once aligned, these arrays sculpt a magnetic field. The field can be one-sided, neutralized at one point, and metal filings are used to demonstrate the shape of these fields in a quick video. In the video after the break, a powerful magnetic field is built but when a rare earth magnet is placed in the center, rather than blasting into one of the nearby magnets, it wobbles lazily.

Be careful when working with powerful magnets, they can pinch and crush, but go ahead and build your own levitating flyer or if you came for hoverboards, check out this hoverboard built with gardening tools.

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Soda Can Art

May 2, 2018 by Anool Mahidharia 37 Comments

A can of soda costs about half a dollar, and once you’re done with the sugary syrup, most cans end up in the trash headed for recycling. Some folks re-use them for other purposes, but we’re guessing no one up-cycles them quite like artist [Noah Deledda] does. He turns them into pieces of Soda Can art that sell for anywhere between $2000 to $3000 a pop.

Don’t be fooled by that smashing hit in the GIF. It’s just some trick photography that [Noah] did to impress people. If you looked at the end product without the back story first, you’d think the cans were manipulated in to contorted shapes using some kind of mechanical assistance, at the very least, or probably a purpose-built machine.

But [Noah Deledda] does it with bare hands. This is the bare-metal version of Origami. While on a road trip many years ago, he was bereft of electronic devices to keep him busy. Playing with an empty can of soda, he started denting and squeezing the thin metal in to an abstract shape. That’s when the artist in him realized that he was playing with an exciting new medium. After making some abstract art pieces out of empty cans of a vermillion bovine energy drink, he figured it would look much more awesome if he could remove all the paint from the cans and give them a smooth, polished, natural finish. He made a little machine that rotates the cans so he can strip the paint and bring the cans to a high polish. The technique is simple but requires a lot of patience, practice, time and skill, not to mention that it will cause a lot of pain in the thumb.

If you’ve ever been to Japan and drank a can of Kirin Hyoketsu, you’d notice the un-opened can is smooth, but immediately changes to a pattern of indented diamonds once you open it. That design was created by Kyoro Miura, well-known for the Miura Fold that lets you fold and unfold large sheets of paper in one smooth movement. Like that discarded map in the glove box of the car you’re riding in, while playing with an empty can of soda.

If you want to hone some ambidextrous skills, this would be a good way to do it while on your next road, plane or train trip. Check out the two videos embedded below. In the second one, you can see snapshots of the design process.

Thanks, [Keith O], for this tip.

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