Students Set Sights On DIY Eye Exams

December 23, 2015 by 5 Comments

What if you could give yourself a standard eye exam at home? That’s the idea behind [Joel, Margot, and Yuchen]’s final project for [Bruce Land]’s ECE 4760—simulating the standard Snellen eye chart that tests visual acuity from an actual or simulated distance of 20 feet.

This test is a bit different, though. Letters are presented one by one on a TFT display, and the user must identify each letter by speaking into a microphone. As long as the user guesses correctly, the system shows smaller and smaller letters until the size equivalent to the 20/20 line of the Snellen chart is reached.

Since the project relies on speech recognition, the group had to consider things like background noise and the differences in human voices. They use a bandpass filter to screen out frequencies that fall outside the human vocal range. In order to determine the letter spoken, the PIC32 collects the first 256 and last 256 samples, stores them in two arrays, and performs FFT on the first set. The second set of samples undergoe Mel transformation, which helps the PIC assess the sample logarithmically. Finally, the system determines whether it should show a new letter at the same size, a new letter at a smaller size, or end the exam.

While this is not meant to replace eye exams done by certified professionals, it is an interesting project that is true to the principles of the Snellen eye chart. The only thing that might make this better is an e-ink display to make the letters crisp. We’d like to see Snellen’s tumbling E chart implemented as well for children who don’t yet know the alphabet, although that would probably require a vastly different input method. Be sure to check out the demonstration video after the break.

Don’t know who [Bruce Land] is? Of course he’s an esteemed Senior Lecturer at Cornell University. But he’s also extremely active on Hackaday.io, has many great embedded engineering lectures you can watch free-of-charge, and every year we look forward to seeing the projects — like this one — dreamed and realized by his students. Do you have final projects of your own to show off? Don’t be shy about sending in a tip!

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Before Google There Was The Chemical Rubber Company

December 23, 2015 by 40 Comments

Quick. What’s the difference in conductivity between silver and copper? Today, that’s easy to find out. You just ask Google (maybe even out loud if you have a phone handy). But it wasn’t that long ago that you needed another option. Before the Internet age, a big part of being “that guy” (or gal) was knowing where to go to find things. You had to be a master of the library’s reference section, know what might be in an encyclopedia or an almanac.

However if you were a hardcore math, science, or engineering geek you probably had, at least, one edition of CRC handbooks. Today, we usually think of CRC as cyclic redundancy check, but back then it was the Chemical Rubber Company.

The Chemical Rubber Company dates back to 1903 when brothers Arthur, Leo, and Emanuel Friedman were selling rubber lab aprons in Cleveland, Ohio (Arthur, apparently, had been in a similar business from 1900). In 1913, the brothers offered a short (116-page) booklet called the Rubber Handbook free with the purchase of a dozen aprons.

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USB Proxy Rats Out Your Devices’ Secrets

December 23, 2015 by 19 Comments

If you need to reverse-engineer a USB protocol on a computer running Linux, your work is easy because you control everything on the target system — you can just look at the raw USB data. If you’d like to reverse-engineer a USB device that plugs into a game console, on the other hand, your work is a lot harder. Until now.

serialusb is a side-project by [Mathieu Laurendeau], alias [Matlo]. His main project, GIMX is aimed at gaming and lets you modify your gaming controller’s performance by passing it first through your PC and tweaking the USB data before forwarding it on to the target console. Want rapid fire? You got it. Alter the steering-wheel sensitivity curves? Sure.

GIMX is essentially a USB man-in-the-middle between your controller and your console, with the added ability to modify the data along the way. For hardware that’s not yet supported by GIMX, though, either [Matlo] would need to borrow your controller, or teach you to man-in-the-middle your own USB traffic. And that’s what serialusb does.

The hardware required is very modest: a USB-to-serial adapter and an ATmega32u4-based Arduino clone. Many of you could whip this together with parts on hand, and it’s the same hardware you’d need to run GIMX anyway. Data goes through your computer, is usbmon’ed and wireshark’ed, and then passed over serial to the ATmega which then converts it back into USB, plugged into the console. A very tidy little setup.

In case this seems familiar, we’ve covered a similar trick by [Matlo] before that used a BeagleBoard as the computer in the middle. That’s a sweet setup for sure, but if you don’t have a spare single-board computer lying around, now you can get it done for only around $5 in parts. Happy USB reversing!

God On The CB Radio

December 23, 2015 by 37 Comments

Sometimes art pushes boundaries. We’ve covered a lot of tech art that blurs the lines between the craft of engineering and high-concept art theory. Praydio, by [Niklas Roy] and [Kati Hyyppä] leans easy on the tech, but pushes against viewers’ religious sensibilities.

Playing with the idea of talking directly to God, and with the use of altars as a focal point to do so, [Niklas] and [Kati] took the extremely literal route: embedding a CB radio into a dollar-store shrine. The result? If you’re lucky, someone will answer your prayers, although we’re not too hopeful that the intervention will be divine.

The art critic in us would say that this is a radical democratization of religious authority in that anyone who is tuned in can play the role of Jesus. Or maybe we’d say something about the perception of religious significance in the seemingly random events of our everyday life — maybe it’s not just chance that someone is tuning in at the time you’re asking for help?

Honestly, though, we think they’re just having a bit of fun. The video (below the break) shows someone asking Jesus for a coffee, and the artist on the other end laughs and fetches him one. It’s not high-tech, and it’s not even amateur radio the way we usually think of it, but something about the piece made us laugh, and then to think for a bit. Even if this art isn’t your style, check out [Niklas’] website — he’s got tons of fun projects written up, a few of which we’ve covered here before.

The Return Of The Screen Savers

December 22, 2015 by 29 Comments

If you were lucky enough to have cable TV back in 1998, you may remember a fledgling channel called “TechTV.” The crown jewel of the network was a show called “The Screen Savers.” Well, recently the TWiT Network has relaunched the show (without the partnership or permission from the old producers) as “The New Screen Savers” – and it’s almost exactly as we remembered it. The show features tech news, tip and tricks – starring the lovable [Leo Laporte] as the main host.

We’ll assume that most Hackaday readers are at a level of knowledge above what’s generally presented in the show, but we have to admit that we almost always find some little tech tip or software review that we didn’t know about. And if you know someone who is starting to take an interest in all things tech, this might be a great way for them to start learning quickly – and to gain exposure to a wide variety of topics.

If you’re looking for a bit of nostalgia, many of the co-hosts of the old show return regularly. People like [Kevin Rose], [Patrick Norton] and [Sarah Lane]. You can watch the show on the TWiT site or on YouTube. We’ve included the first episode after the break.

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Engauge Makes Graph Thieving A Cinch

December 22, 2015 by 9 Comments

We’ve seen ’em before: the charts and graphs in poorly photocopied ’80s datasheets, ancient research papers, or even our college prof’s chalkboard chicken scratch. Sadly, this marvelously plotted data is locked away in a poorly rendered png or textbook graphic. Fortunately, a team of programmers have come the rescue to give us the proper thieving tool to lift that data directly from the source itself, and that tool is Engauge.

Engauge is an open source software tool that enables to convert pictures of plots into the numerical representation of their data. While some of us might still be tracing graphs by hand, Engauge enables us to simply define reference points on the graph, and a clever image-processing algorithm extracts the curve for us automatically! Sure, there’s a little fine-tuning to determine what counts as data, but the net result is an all-in-one software tool that eats pictures and produces data–no intermediate steps required!

Engauge has been helping scientists and engineers preserve ancient data logs for years now, but it’s a tool that’s still fresh today when we’re recording from an analog o’scope or lifting those xs and ys off a textbook. In a world that’s increasingly digital, we’ve got the Engague developers to thank for arming us with the right tool for the job. All that said, If graph-thieving isn’t your thing, try spline-thieving to go from camera to CAD.

Engauge is a little lacking in the demo-video department, but we dug up a quickie on YouTube.

Thanks for the tip, [Jason]!

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Retrotechtacular: Electronic Publishing In The 1930s

December 22, 2015 by 12 Comments

We are living in the age of citizen journalism and the 24-hour news cycle. Reports about almost anything newsworthy can be had from many perspectives, both vetted and amateur. Just a few decades ago, people relied on daily newspapers, radio, and word of mouth for their news. On the brink of the television age, several radio stations in the United States participated in an experiment to broadcast news over radio waves. But this was no ordinary transmission. At the other end, a new type of receiver printed out news stories, line drawings, and pictures on a long roll of paper.

Radio facsimile newspaper technology was introduced to the public at the 1939 World’s Fair at two different booths. One belonged to an inventor named William Finch, and one to RCA. Finch had recently made a name for himself with his talking newspaper, which embedded audio into a standard newspaper in the form of wavy lines along the edges that were read by a special device.

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