The Science Behind Boost Converters

May 5, 2017 by Jack Laidlaw 30 Comments

[Ludic Science] shows us the basic principles that lie behind the humble boost converter. We all take them for granted, especially when you can make your own boost converter or buy one for only a few dollars, but sometimes it’s good to get back to basics and understand exactly how things work.

The circuit in question is probably as simple as it gets when it comes to a boost converter, and is not really a practical design. However it helps visualize what is going on, and exactly how a boost converter works, using just a few parts, a screw, enameled wire, diode, capacitor and a push button installed on a board.

The video goes on to show us the science behind a boost converter, starting with adding a battery from which the inductor stores a charge in the form of an electromagnetic field. When the button is released, the magnetic field collapses, and this causes a voltage in the circuit which is then fed through a diode and charges the capacitor a little bit. If you toggle the switch fast enough the capacitor will continue to charge, and its voltage will start to rise. This then creates a larger voltage on the output than the input voltage, depending on the value of the inductor. If you were to use this design in a real life application, of course you would use a transistor to do the switching rather than a push button, it’s so much faster and you won’t get a sore finger.

This is very basic stuff, but the video gives us a great explanation of what is happening in the circuit and why. If you liked this article, we’re sure you’ll love Hackaday’s own [Jenny List] explain everything you need to know about inductors.

(updated thanks to [Unferium] – I made a mistake about the magnetic field collapsing when the button is pressed , When in reality it’s when the button is released that this happens. Apologies for confusion.)

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Gain Access To Science Two Ways

April 15, 2017 by Elliot Williams 56 Comments

Not a hack, but something we’ve been wanting to see forever is open access to all scientific publications. If we can soapbox for a few seconds, it’s a crying shame that most academic science research is funded by public money, and then we’re required to pay for it again in the form of journal subscriptions or online payments if we want to read it. We don’t like science being hidden behind a paywall, and neither do the scientists whose work is hidden from wider view.

Here are two heartening developments: Unpaywall is a browser extension that automates the search for pre-press versions of a journal article, and the Bill and Melinda Gates Foundation are denying rights to research that it has funded if the resulting publications aren’t free and open.

The concept of “publishing” pre-print versions of academic papers before publication is actually older than the World Wide Web — the first versions of what would become arXiv.org shared LaTeX version of physics papers and ran on FTP and Gohper. The idea is that by pushing out a first version of the work, a scientist can get early feedback and lay claim to interesting discoveries prior to going through the long publication process. Pre-prints are available in many other fields now, and all that’s left for you to do is search for them. Unpaywall searches for you.

Needless to say, this stands to take a chunk out of the pocketbooks of scientific publishers. (Whether this matters in comparison to the large fees that they charge libraries, universities, and other institutional subscribers is open to speculation.) The top-tier journals — Nature, Science, the New England Journal of Medicine, and others — have been reluctant to offer open access, so brilliant scientists are faced with the choice of making their work openly available or publishing in a prestigious journal, which is good for their career.

In a step to change the status quo, the Bill and Melinda Gates Foundation took their ball and went home; research funded with their money has to be open-access, period. We think that’s a laudable development, and assuming that the foundation funds quality research, the top-tier journals will be losing out unless they cooperate.

To be fair to the journal publishers, many journals are open-access or have open-access options available. The situation today is a lot better than it was even five years ago. But if we had a dime for every time we try to research some scientific paper and ran into a paywall, we wouldn’t be reduced to hawking snazzy t-shirts.

Thanks [acs] for the tip!

PUFFER: A Smartphone-Sized Planetary Explorer

April 8, 2017 by James Hobson 13 Comments

Is there room on Mars and Europa for cute robots? [NASA] — collaborating with [UC Berkley] and [Distant Focus Corporation] — have the answer: PUFFER, a robot inspired by origami.

PUFFER — which stands for Pop-Up Flat-Folding Explorer Robot — is able to sense objects and adjust its profile accordingly by ‘folding’ itself into a smaller size to fit itself into nooks and crannies. It was designed so multiple PUFFERs could reside inside a larger craft and then be deployed to scout otherwise inaccessible terrain. Caves, lava tubes and shaded rock overhangs that could shelter organic material are prime candidates for exploration. The groups of PUFFERs will send the collected info back to the mother ship to be relayed to mother Earth.

We’ve embedded the video of the bot folding it’s wheels down to pass a low-bridge. You can get a view of the wider scope of functionality for the collection of demos on the project page.

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NASA’s 2017-2018 Software Catalog Is Out

March 16, 2017 by Elliot Williams 16 Comments

Need some help sizing your beyond-low-Earth-orbit vehicle? Request NASA’s BLAST software. Need to forecast the weather on Venus? That would be Venus-GRAM (global reference atmospheric model). Or maybe you just want to play around with the NASA Tensegrity Robotics Toolkit. (We do!) Then it’s a good thing that part of NASA’s public mandate is making their software available. And the 2017-2018 Software Catalog (PDF) has just been released.

Unfortunately, not everything that NASA does is open source, and a substantial fraction of the software suites are only available for code “to be used on behalf of the U.S. Government”. But still, it’s very cool that NASA is opening up as much of their libraries as they are. Where else are you going to get access to orbital debris engineering models or cutting-edge fluid dynamics modelers and solvers, for free?

We already mentioned this in the Links column, but we think it’s worth repeating because we could use your help. The catalog is 154 pages long, and we haven’t quite finished leaf through every page. If you see anything awesome inside, let us know in the comments. Do any of you already use NASA’s open-source software?

Microfluidics “Frogger” Is A Game Changer For DIY Biology

January 16, 2017 by Dan Maloney 30 Comments

See those blue and green dots in the GIF? Those aren’t pixels on an LCD display. Those are actual drops of liquid moving across a special PCB. The fact that the droplets are being manipulated to play a microfluidics game of “Frogger” only makes OpenDrop v 2.0 even cooler.

Lab biology is mainly an exercise in liquid handling – transferring a little of solution X into some of solution Y with a pipette. Manual pipetting is tedious, error prone, and very low throughput, but automated liquid handling workstations run into the hundreds of thousands of dollars. This makes [Urs Gaudenz]’s “OpenDrop” microfluidics project a potential game changer for the nascent biohacking movement by offering cheap and easy desktop liquid handling.

Details are scarce on the OpenDrop website as to exactly how this works, but diving into the literature cited reveals that the pads on the PCB are driven to high voltages to attract the droplets. The PCB itself is covered with a hydrophobic film – Saran wrap that has been treated with either peanut oil or Rain-X. Moving the droplets is a simple matter of controlling which pads are charged. Splitting drops is possible, as is combining them – witness the “frog” getting run over by the blue car.

There is a lot of cool work being done in microfluidics, and we’re looking forward to see what comes out of this open effort. We’ve covered other open source efforts in microfluidics before, but this one seems so approachable that it’s sure to capture someone’s imagination.

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Hacked Diamond Makes Two-Atom Radio

December 20, 2016 by Dan Maloney 14 Comments

It used to be pretty keen to stuff a radio receiver into an Altoid’s tin, or to whip up a tiny crystal receiver from a razor blade and a pencil stub. But Harvard researchers have far surpassed those achievements in miniaturization with a nano-scale FM receiver built from a hacked diamond.

As with all such research, the experiments in [Marko Lončar]’s lab are nowhere near as simple as the press release makes things sound. While it’s true that a two-atom cell is the minimal BOM for a detector, the device heard belting out a seasonal favorite from [Andy Williams] in the video below uses billions of nitrogen-vacancy (N-V) centers. N-V centers replace carbon atoms in the diamond crystal with nitrogen atoms; this causes a “vacancy” in the crystal lattice and lends photoluminescent properties to the diamond that are sensitive to microwaves. When pumped by a green laser, incident FM radio waves in the 2.8 GHz range are transduced into AM fluorescent signals that can be detected with a photodiode and amplifier.

The full paper has all the details, shows that the radio can survive extreme pressure and temperature regimes, and describes potential applications for the system. It’s far from a home-gamer’s hack at this point, but it’s a neat trick and one to watch for future exploitation. In the meantime, here’s an accidental FM radio with a pretty small footprint.

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Mexican Highschoolers Launch 30 High Altitude Balloons

December 5, 2016 by Elliot Williams 15 Comments

No matter whether you call them “picosatellites” or “high altitude balloons” or “spaceblimps”, launching your own electronics package into the air, collecting some high-altitude photos and data, and then picking the thing back up is a lot of fun. It’s also educational and inspirational. We’re guessing that 264 students from 30 high schools in Aguascalientes Mexico have new background screens on their laptops today thanks to the CatSat program (translated here by robots, and there’s also a video to check out below).

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