Fail Of The Week: How A Cheap USB AC Adapter Might Indirectly Burn Your House Down

November 28, 2013 by Mathieu Stephan 41 Comments

This Fail of the Week will remind our readers that every project they make, no matter how small they might be, may have big consequences if something goes wrong. Shown in the picture above is an oven that [Kevin] tweaked to perform reflow soldering. The story is he had just moved into a new place a few weeks ago and needed to make a new batch of boards. As he had cycled this oven many times, he was confident enough to leave the room to answer a few emails. A few minutes later, he had the unfortunate experience of smelling something burning as well as discovering white smoke invading his place.

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Retrotechtacular: WWII Paraset Spy Radio Used By French Resistance

November 26, 2013 by Todd Harrison 16 Comments

[Robert Sumption] a.k.a [W9RAS] takes on the daunting challenge of building a WWII spy radio called the Paraset as the topic of this week’s Retrotechtacular. It was originally a tube based CW (Morse code) transmitter/receiver used by the French underground to communicate with the Allies. Many of these radios were dropped behind enemy lines and could run on European AC or 6 V DC with the added advantage of being able to use most anything for an antenna, including fence wire. These small, low power and highly mobile radios tuned in the 3 to 8 MHz range were instrumental in the resistance. But they still make for a really fun scratch-built radio project.

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Hacking And Philosophy: Crackdown Part III

November 25, 2013 by Marsh 21 Comments

h&pcrackdown3

“Law and Order” may be my favorite chapter of Hacker Crackdown: it covers the perspective of the early 90’s seizures and arrests from the perspective of law enforcement. While the chapter has its flaws, I highly recommend it; [Sterling] treats both sides with patience and understanding, revealing how similarly adrift everyone was (and to some extent, remains) in the uncertainty of cyberspace. I also recommend the [Gail Thackeray] / [Dead Addict] joint talk from DEFCON 20 as an accompanying piece to this chapter, as it bridges the twenty-year gap between Crackdown‘s publication and today—and [Thackeray] herself is the focus of this chapter.

As always, everyone is welcome in our weekly discussion, even if you haven’t been keeping up with our progress through Hacker Crackdown. You can download it for free as an audiobook, too! Onward for more!

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Hackaday Links: November 24, 2013

November 24, 2013 by Mike Szczys 4 Comments

We love home theater hacks and this one especially since it is also part of a larger home automation project. [Falldeaf] use Z-Wave wireless home automation and includes mains switching for his television. The only problem being that when power is switch back on the TV remains in the standby state. His solution was to use an ATtiny85 to detect power, then push the IR code to turn the TV on after a short delay.

[Pjkim] wanted to prototype using the Tiva Launchpad on his Mac. He managed to get a toolchain up and running that includes the TivaWare libraries. He put together a guide that shows how to set up Eclipse and Energia for the Tiva family. If you haven’t heard of Energia check out the Github Readme.

Most folks have a smartphone and you can bet that the handsets are Bluetooth enabled. But we think there is still a low percentage who are connecting their smartphone audio to wireless speakers. [Anton Veretenenko] shows how you can use some cheap KRC-86B modules from Ali Express to make your own wireless speakers. He’s even powering his hack with a single 18650 Li-Ion cell.

Taking a turn away from electronics we got a chuckle out of [CADFood’s] plan to make pearls with his bicycle. He used DesignSpark Mechanical to model what amounts to a bicycle powered ball mill. It attaches to his spokes and after taking a hammer to some oyster shells he loads them up and goes for a ride. Well actually he needs to go for a bunch of rides. The idea is that about six months of bicycling will yield a cache of pearls. [Thanks Holger]

We enjoyed this article on how designing powered scooters is changing engineering education. We’re happy to see that hacking is starting to be widely accepted as a functional and effective way to gain and pass on knowledge.

If you have access to a 3D printer you can own some of the relics from the Smithsonian. They’ve been 3D scanning some pieces in their collection and you can download the models.

And finally, [GravityRoad] is working on building a delta-bot arm to use as part of a performance art project. Check out one of the most recent development videos and if that gets you interested there’s much more on the website. [Thanks Charles]

Fail Of The Week: Commute-Shortening Electric Scooter

November 21, 2013 by Mike Szczys 38 Comments

Please don’t judge [Alan] on his choice of vests. This project is from 1999 when it was common to see people rockin’ these threads. Anyone who has ever spent time on the University of Minnesota campus in Minneapolis, Minnesota will know that parking is at a premium. [Alan] had a 12-15 minute walk from his parking garage to his office and was considering a cheaper parking location that would balloon that to 20-25 minutes. But engineers don’t see problems, they see project ideas. He started work on a tiny electric scooter that could slim down his commute. Obviously he did find some success, but it was interspersed with failures that make his scooter the Fail of the Week.

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3D Printering: Wherein ABS Is Dangerous

November 20, 2013 by Brian Benchoff 84 Comments

A lot of the ‘prosumer’ – for as much as I hate that word – 3D printers out there like the Makerbot Replicator and countless other Kickstarter projects only officially support PLA filament. This has a few advantages from a product development standpoint, namely not necessitating the use of a heated build plate. There are other reasons for not supporting ABS and other filaments, as one of the Kickstarter updates for the Buccaneer printer elucidates (update available to backers only, here’s a mirror from somebody on reddit).

The main crux of the Buccaneer team’s decision not to support ABS is as follows:

We spoke to our legal counsel about it and they told us that if we officially support a certain “material” type then our printer has to go through massive certification to prove that it is totally safe to use or we will/can get sued badly.

Despite the Buccaneer team’s best efforts, we’re sure, their lawyers were actually able to find some studies that showed ABS could affect a person’s health. The issue isn’t with the ABS itself – LEGO are made of ABS and kids chew on blocks all the time. The issue comes from the decomposition of ABS when it is heated.

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Retrotechtacular: [Zoltán Bay’s] Moon Bounce Coulometer Signal Amplifier

November 19, 2013 by Todd Harrison 15 Comments

In the years before World War II it was theorized that shortwave radio waves could propagate through the ionosphere relatively undisturbed and allow for a signal to be bounced off the moon and returned. [Zoltán Bay] calculated that the return signal would be too faint to be detected above background noise with the radio receiving equipment of the day. To overcome this receiver dilemma he devised a new receiving element consisting of 10 coulometers sharing a common tank of a water solution. Each of the coulometers had a separate electrical connector and when current flowed through the electrode, hydrogen bubbles would form in an attached glass capillary column. By periodically sweeping through all 10 coulometers using a rotating switch attached to the radar receiver, any radar echo as well as random background noise would be readable by the amount of bubbles in the capillary columns. A single radar echo would be indistinguishable from random background noise in the columns of bubbles, but if the sweep is continued for 30 minutes any periodic radar echo would show as an increased accumulation of bubbles in a respective column. By reading these coulometers and knowing the switching period you could determine that you were receiving a true radar echo from the moon.

What an amazing apparatus to amplify a periodic signal above background noise! Nowadays we would call this a long-time integrator or persistence measurement and it’s a relatively simple task. You can download and read [Zoltán Bay’s] paper on “Reflection of Microwaves From the Moon” dated 1946 in PDF form. His integrator apparatus details start on page 17.

It took some years but in 1946 [Zoltán Bay’s] receiving apparatus was tested and did confirm reception from moon bounce. However, U.S. Army Signal Corps with better crystal frequency stabilized equipment was able to perform the same task earlier as seen in the below video without the use of an integrator. Even though the U.S. Army equipment was superior for this task [Zoltán Bay’s] apparatus enjoyed years of service in the field of planetary radar observation where such a high sensitivity scheme was still necessary.

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