Author: Elliot Williams

1434 Articles

The Original Seven (Eight?) Segment Display

January 9, 2015 by 36 Comments

The seven-segment LED display is ubiquitous. But how old do you think the fundamental idea behind it is? You nixie tube fans will be thinking of the vacuum-tube era, but a reader sent us this patent filed in 1908 where [Frank W. Wood] builds a numeric display with plain-vanilla light bulbs, slots cut in wood, and lots of wires.

The OCR on the patent is poorly done — you’re going to want to download the PDF and read it locally. But as it states in the patent, “Referring again to Fig. 1, the novel arrangement of the lamp compartments will be readily understood.”

Technically it’s not a seven-segment display at all. [F.W. Wood] designed these really nice-looking “4”s with the diagonal heads, and so he needed eight segments per digit. But the basic idea shines through, if you pardon the pun.

The other figures demonstrate the machine that’s used to send the signals to light up the lights. It’s a rotating drum with the right contacts on the bottom side to make connections and turn on the right lights at the other end. Low tech, but it’s what was available at the time.

We’re stoked that we’re not responsible for wiring this thing up, and we’re a bit awed by how old the spirit behind one of our most ubiquitous technologies is.

Thanks to [mario59] for the nostalgic tip!

Global Space Balloon Challenge

January 7, 2015 by 20 Comments

Looking for a reason to put up a balloon and payload into near-space? Not that one’s necessary, but the Global Space Balloon Challenge has got a variety of good reasons for you to do so, in the form of prizes and swag from their sponsors. Go for highest altitude, best photograph, longest ground track, best on-board science payload, or a bunch more. Have a look through the gallery to check out last year’s winners, including teams that dropped a 3ft paper airplane or floated an R2D2 replica.

Basically all you need to do is register on their website and then go fly a high-altitude balloon between April 10th and 27th. Last year 60 teams took part, and this year they’ve already got 90 teams from 31 countries.

And if you’re just getting into the (hobby? sport?) of high-altitude ballooning, be sure to check out their tutorials and forum. Of course Hackaday has been covering folks’ near-space balloon efforts for a while now too, so you’ve got plenty of reading.

So what are you waiting for? Helium’s not getting any cheaper and spring is on its way. Start planning your balloon launch now.

Pendulum Music For Oscilloscope And Photodiodes

December 28, 2014 by 9 Comments

Two turntables and a microphone? Try two oscilloscopes and a couple of photodiodes. [dfiction] reinterpreted Steve Reich’s classic feedback piece for more modern electronics. The video is embedded after the break.

The original Pendulum Music is a conceptual musical composition from the heady year of 1968. Basically, you set a bunch of microphones swinging across speakers, making feedback as they pass by. The resulting rhythmic and tonal oscillations change over time as the swinging damps down. It’s either mesmerizing or entirely boring, depending on your mindset.

In the [dfiction] version, the feedback is produced by passing a “light microphone” over an oscilloscope. And since he’s got a pair of these setups, the one microphone also feeds the other ‘scope. The resulting sound is this chaotic and gritty noise-rumble. We dig it.

If slowly evolving “process music” pushes the boundaries of your attention span (or if it’s just not your thing) you can totally skip around in the video. Try around 1:40 and 3:45 into the piece just to get an idea of what’s going on. But once you’re there, you might as well let it run its course.

Continue reading “Pendulum Music For Oscilloscope And Photodiodes” →

31st Chaos Communications Congress

December 27, 2014 by 10 Comments

The 31st annual Chaos Communications Congress (31C3) kicked off today and you’ve already missed some great talks. If you’re not in Hamburg, Germany right now, you can watch the talks as they happen on the live stream. So stop reading this blog post right now, and check out the list of presentations. (But don’t fret if you’ve already missed something that you’d like to see. All the talks are also available after the fact.)

For those of you whose worldview is centered firmly on the You Ess of Ay, you’ll be surprised to learn that the Congresses are essentially the great-grandaddy of the US hacker conventions. If you’re one of the many (old?) US hackers who misses the early days of yore before DEFCON got too slick and professional, you’ll definitely like the CCC. Perhaps it’s the German mindset — there’s more emphasis on the community, communication, and the DIY aesthetic than on “the industry”. It’s more HOPE than DEFCON.

This is not to say that there won’t be some great hacking showcased at 31C3. It is the annual centerpiece of the European hacker scene, after all. Hardware, firmware, or software; it’s all exploited here.

Some of the talks are in German, naturally, but most are in English. If you haven’t attended before, you at least owe it to yourself to check out the live stream. Better yet, if you’re a member of an American hackerspace, you can at least set up local remote viewing for next year. Or maybe you’ll find yourself visiting Germany next Christmas.

[Image: Wikipedia / Tobias Klenze / CC-BY-SA 3.0]

Towards The Perfect Coin Flip: The NIST Randomness Beacon

December 19, 2014 by 75 Comments

Since early evening on September 5th, 2013 the US National Institute of Standards and Technology (NIST) has been publishing a 512-bit, full-entropy random number every minute of every day. What’s more, each number is cryptographically signed so that you can easily verify that it was generated by the NIST. A date stamp is included in the process, so that you can tell when the random values were created. And finally, all of the values are linked to the previous value in a chain so that you can detect if any of the past numbers in the series have been altered after the next number is published. This is quite an extensive list of features for a list of random values, and we’ll get into the rationale, methods, and uses behind this scheme in the next section, so stick around.

Continue reading “Towards The Perfect Coin Flip: The NIST Randomness Beacon” →

Reverse Engineering Super Animal Cards

December 11, 2014 by 15 Comments

If you don’t have a niece or nephew we encourage you to get one because they provide a great excuse to take apart kids’ toys.

[Sam] had just bought some animal-themed trading cards. These particular cards accompany a card-reader that uses barcodes to play some audio specific to each animal when swiped. So [Sam] convinces her niece that they should draw their own bar codes. Of course it’s not that easy: the barcodes end up having even and odd parity bits tacked on to verify a valid read. But after some solid reasoning plus trial-and-error, [Sam] convinces her niece that the world runs on science rather than magic.

But it can’t end there; [Sam] wants to hear all the animals. Printing out a bunch of cards is tedious, so [Sam] opens up the card reader and programs and Arduino to press a button and blink an IR LED to simulate a card swipe. (Kudos!) Now she can easily go through all 1023 possible values for the animal cards and play all the audio tracks, and her niece gets to hear more animal sounds than any child could desire.

Along the way, [Sam] found some interesting non-animal sounds that she thinks are Easter eggs but we would wager are for future use in a contest or promotional drawing or something similar. Either way, its great fun to get to listen in on more than you’re supposed to. And what better way to educate the next generation of little hackers than by spending some quality time together spoofing bar codes with pen and paper?

Popular Electronics Magazine Archive Online

December 3, 2014 by 43 Comments

They began publishing Popular Electronics magazine in 1954, and it soon became one of the best-selling DIY electronics magazines. And now you can relive those bygone days of yore by browsing through this archive of PDFs of all back issues from 1954 to 1982.

Reading back through the magazine’s history gives you a good feel for the technological state of the art, at least as far as the DIYer is concerned. In the 1950s and 1960s (and onwards) radio is a big deal. By the 1970s, hi-fi equipment is hot and you get an inkling for the dawn of the digital computer age. Indeed, the archive ends in 1982 when the magazine changed its name to Computers and Electronics magazine.

It’s fun to see how much has changed, but there’s a bunch of useful material in there as well. In particular, each issue has a couple ultra-low-parts-count circuit designs that could certainly find a place in a modern project. For example, a “Touch-Controlled Solid State Switch” in July 1982 (PDF), using a hex inverter chip (CD4049) and a small handful of passive components.

But it’s the historical content that we find most interesting. For instance there is a nice article on the state of the art in computer memory (“The Electronic Mind — How it Remembers”) in August 1956 (PDF).

Have a good time digging through the archives, and if you find something you really like, let us know in the comments.