Muscle Wire Pen Dances To Duke Nukem

December 22, 2015 by Elliot Williams 2 Comments

[serdef] is clearly just having a little bit of fun here. One never needs a whiteboard pen that’s syncronized by MIDI to dance along with the theme from Duke Nukem.

But if you had all of the parts on hand (a highly liquid MIDI-driven relay board that connects straight up to a soundcard, some muscle wire, tape, and a whiteboard pen, naturally) we’re pretty sure that you would. You can watch the dancing pen in a video below the break.

The project is really about documenting the properties of [serdef]’s muscle wire, and he found that it doesn’t really contract enough with a short piece to get the desired effect. So he added more wire. We’ve always meant to get around to playing with muscle wire, and we were surprised by how quickly it reacted to changing the voltage in [serdef]’s second video.

Now the dancing pen isn’t the most sophisticated muscle wire project we’ve ever seen. And that award also doesn’t go to this Nitinol-powered inchworm. Did you know that there’s muscle wire inside Microsoft’s Surface?

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Scratching Vinyl Straddles Physical And Digital Realms

December 21, 2015 by Elliot Williams 10 Comments

The life of a modern DJ is hard. [Gergely] loves his apps, but the MIDI controller that works with the app feels wrong when he’s scratching, and the best physical interfaces for scratching only work with their dedicated machines. [Gergely]’s blog documents his adventures in building an interface to drive his iPad apps from a physical turntable. But be warned, there’s a lot here and your best bet is to start at the beginning of the blog (scroll down) and work your way up. Or just let us guide you through it.

In one of his earliest posts he lays out his ideal solution: a black box that interprets time-code vinyl records and emulates the MIDI output of the sub-par MIDI controller. Sounds easy, right? [Gergely] gets the MIDI side working fairly early on, because it’s comparatively simple to sniff USB traffic and emulate it. So now he’s got control over the MIDI-driven app, and the hard part of interfacing with the real world began.

After experimenting a lot with timecode vinyl, [Gergely] gives up on that and looks for an easier alternative. He also considers using an optical mouse, but that turns out to be a dead-end as well. Finally, [Gergely] settled on using a Tascam TT-M1, which is basically an optical encoder that sits on top of the record, and that makes the microcontroller’s job a lot easier. You can see the result in the video below the break.

And then in a surprise ending worthy of M. Night (“I see dead people”) Shyamalan he pulls timecode vinyl out of the grave, builds up a small hardware translator, and gets his original plan working. But we have the feeling that he’s not done yet: he also made a 3D printed optical-mouse holder.

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No Spectrum Analyser? No Problem!

December 20, 2015 by Elliot Williams 18 Comments

In the Bad Old Days, a spectrum analyser was a big piece of expensive machinery that you’d have on your bench next to your oscilloscope. And while good ones still cost a ton of money, [rheslip] shows you how to turn your VISA-compatible scope into a decent spectrum analyser for the low, low price of nothing. Watch it in action in the video below the break.

If your scope is relatively recent, like this side of the late 1990s, it might support National Instrument’s VISA: virtual instrument software architecture. [rheslip]’s Rigol scope does, and he uses PyVisa, a Python wrapper for the NI-VISA libraries to download the raw samples from the ‘scope and then crunches the FFTs out on his laptop.

There are definitely drawbacks to this method. The sampling depth of the scope is eight bits, which limits his maximum signal-to-noise ratio, and the number-crunching and data transfer are slow, resulting in a 2 Hz refresh rate. But once the data has made it across to his laptop, [rheslip] can run the FFTs at whatever sample length he wants, resulting in very high frequency resolution.

Indeed, we’re thinking that there’s all sorts of custom filters and analysis that one could do with raw access to the oscilloscope’s data. Why haven’t we been doing this all along? Any of you out there have cool VISA tricks that you’d like to share?

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Tokyo Police Aim To Catch Drones In A Net

December 20, 2015 by Elliot Williams 39 Comments

A Japanese protester flew a quadcopter with a symbolic amount of soil from the contaminated Fukushima region onto the roof of the Prime Minister’s office in April. Although it was a gesture, it alerted the Tokyo police department to the potential need to be able to pull drones out of the air.

Simply shooting them down won’t do — think of the innocent bystanders on the ground subjected to a rain of quadcopter parts. The Tokyo police’s solution: catch them in a net, flown by another quadcopter, of course.

We can’t embed it here, but go click through to the video. It looks like the police are having a really good time. How long before we see drone-net sets under the Christmas tree, or quadcopter-tag leagues? We’re uncertain of how far the Battlebots in the Sky movement got.

We have no shortage of yahoos driving quadcopters in the States, of course. From interfering with fire-fighting aircraft to simply flying too close to commercial airplanes, people are doing things that they simply shouldn’t. We’ve been covering the US government’s response that finally culminated in the FAA making rules requiring medium-weight drones to be registered. Watch our front page for more on that next week. Fly safe, folks.

[via The Verge]

First Edition Of German Computer Mag Is A Blast From The Past

December 19, 2015 by Elliot Williams 20 Comments

Every once in a while we get nostalgic for the old days of computing. Here, we’re getting nostalgic for a past that wasn’t even our own, but will probably bring a smile to all the German hackers out there. c’t magazine has its first issue available on their website (PDF, via FTP), and it’s worth checking out even if you can’t read a word of German.

It’s dated November/December 1983, and you’re definitely hopping in the WABAC machine here. The cover image is a terminal computer project that you’re encouraged to build for yourself, and the magazine is filled with those characteristic early-computer-era ads, many of them for the physical keyboards that you’d need to make such a device. Later on, c’t would provide plans for a complete DIY PC with plotter, one of which we saw still running at the 2015 Berlin Vintage Computer Festival.

The issue is chock-full of code for you to type out into your own computer at home. If you didn’t have a computer, there are of course reviews of all of the popular models of the day; the TRS-80 Model 100 gets good marks. And if you need to buy a BASIC interpreter, there’s an article comparing Microsoft’s MBASIC with CBM’s CBASIC. A battle royale!

Other hot topics include modifications to make your ZX81’s video output sharper, the hassle of having to insert a coded dongle into your computer to run some software (an early anti-piracy method), and even a computer-music band that had (at least) a Commodore 64 and a CBM machine in their groovy arsenal.

It’s no secret that we like old computers, and their associated magazines. Whether you prefer your PDP-11’s physical or virtual, we’ve got you covered here. And if your nostalgia leans more Anglophone, check out this Byte magazine cover re-shoot.

Bouncing Radio Off Of Airplanes

December 18, 2015 by Elliot Williams 49 Comments

Amateur radio operators are always trying some new stunt or other. It’s like they’ve got something to prove. Take Aircraft scatter for instance: the idea is to extend your radio’s range by bouncing it directionally off of overhead airplanes.

Radio signals travel in straight lines, which is a bummer because the Earth (despite what you’ve heard) is round. Inevitably, if you want to talk to someone far enough away, they’re over a hill. We’ve covered various oddball propagation methods recently, so if you don’t know about moonbounce, you’ve got some background reading to do. But airplane scatter was new to us.

Actually pulling it off requires knowing where the airplanes are, of course. To do so, you could simply look up the aircraft in your target area on the web, using something like FlightRadar24, but where’s the fun in that? There’s also the possibility of tracking local aircraft yourself using RTL-SDR if you’re feeling hard core.

The rest is just details. Hams [Rex Moncur (VK7MO)] and [David Smith (VK3HZ)], for instance, got 10 GHz signals to skip off airplanes over 842 km (PDF). If you’re an old-school ham operator, you’re double-checking the “gigahertz”, but it’s not a mistake. It’s tremendously impressive that these guys got a link over such a long distance using only 10 watts — but note that they’re doing it with highly directive dishes, and telescopes to aim them.

Not to discourage you from trying this at home, but there are all sorts of difficulties that you’ll encounter when you do. Airplanes moving perpendicular to the path between sender and receiver will Doppler-shift the signal, and there’s still quite a chunk of atmosphere to get the signal through. Finally, although airplanes look pretty big when they’re on the ground, they’re actually tiny when they’re up in the sky at 35,000 ft and 500 miles away; you’re bouncing your signal off of a small target.

The good news? People like [W3SZ] are sharing their well-documented results, and at least it’s 20dB easier than bouncing signals off the moon!

Thanks [Martin] for the tip!

A Scam Of Galactic Proportions

December 17, 2015 by Elliot Williams 96 Comments

Here at Hackaday we see a lot of technological hoaxes looking for funding. Some are on Kickstarter, others are firms looking for investors. And unlike a lot of the press, we’re both skeptical and experienced enough to smell the snake oil. When you read about a laser-powered razor blade that looks too good to be true, you know we’ve got your back.

The background: [Zachary Feinstein] is a professor at Washington University in St. Louis who studies financial engineering, and in particular systemic financial risk in the banking sectors. So he’s just exactly the guy you’d tap to write a paper on the financial repercussions of the destruction of the Death Stars in Star Wars (PDF). Wait, what?

The central argument of the paper is that, since the Empire has so much money wrapped up in building the Death Stars, it’s economic suicide for the Rebels to destroy it. To quantify any of this, [Feinstein] runs financial crisis models. The idea is that the Rebels win, but they inherit an economy that’s so dysfunctional that they’d have been better off not destroying the Death Stars.

We’re not saying that the rest of the press is gullible, but we are saying that they’re not putting their best economists onto articles about financing Death Stars. But here at Hackaday, we are. And we’re calling it a hoax. So let’s look into what the paper gets right, and what makes less sense even than Chewbacca’s infernal growling. Spoiler: we’ll get wrapped up in numbers because it’s fun, but the whole thing is moot for Econ 101-style reasons.

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