Fail Of The Week: AFSK Build Doomed By Rail Noise

January 2, 2014 by Mike Szczys 19 Comments

fotw-afsk-rail-noise

[Scott] and his buddies were having some fun with their handheld transmitters one day when they decided it was time to build some add-on hardware that could transmit and receive location data. They set their sights on a set of Audio Frequency Shift Keying units that could each encoded and decipher location from the counterpart.

The build got off to an easy start, centering around an Arduino board with a GPS module for capturing precise location data. Next it was time to implement AFSK. On the transmitting side this was done by bit banging the output pins. After a look at the resulting signals on an oscilloscope the team was able to tune the firmware for a pretty tight 1200 and 2200 Hz output. But trouble was brewing on the decoding side of the equation.

The first decoding attempt used the FreqMeasure library written by [Paul Stoffregen]. After no success they moved to a hardware solution in the form of the XR-2211 FSK Demodulator chip. It should have been simple, feed it the signals and read the digital output pins to capture the desired data. This is the point at which you need to click the project link at the top to soak in all of the gory details. Long story short, a noisy power rail was causing sporadic performance of this chip. By the time this issue was discovered interest had waned and the project was ditched as a failure. Was there a quick fix that could have salvaged it such as adding a filtering circuit for that chip? Let us know how you would get this back on track by leaving a comment below.

[Thanks Lewin]

Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Retrotechtacular: Wax On, Wax Off: How Records Are Made

December 31, 2013 by Kristina Panos 18 Comments

In this 1942 tour of the RCA Victor plant in Camden, NJ, we see the complete record making process from the master cut production to the shipping of multiple 78RPM shellac pressings. The film centers around a recording of Strauss’ Blue Danube waltz as performed by the 1940s equivalent of studio musicians, the Victor Salon Orchestra.

The master record starts life as a thin layer of molten wax poured on to a hot circular plate in a dust-free room. Bubbles and impurities are blow torched out, and the wax is left to cool under a steel dome. This perfect disc is carefully passed to the recording studio through a special slot, where it is laid carefully beneath the cutting stylus.

Unlike today’s multi-track recording sessions, the master was cut from the performance of a complete band or orchestra all playing as they would in concert. The sound engineer was responsible for making fast changes on the fly to ensure sonic and groove width consistency.

After cutting, the delicate wax undergoes several phases of electrolysis that form the metal master. It is bombarded first with pure gold and then twice with copper sulfate to build a sturdy disc. The copper ionization process also ensures high fidelity in the final product.

Although mighty, this master won’t last long enough to make all the necessary pressings, so a mother matrix is made. This is a negative image of the master. The mother is formed by electrolytically bathing the master in nickel, and then adding a thin film of some indeterminate substance. Another copper bath, and mother emerges. As soon as possible, the master is separated and whisked away to the storage vault.

Since a positive image is needed for pressing, a stamping matrix is made. Mother gets a nickel bath for durability, and then a copper bath to form the stamping matrix. Many stampers are created so that several records can be pressed at once. These images get a chromium plating to help them last through many pressings.

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Hacking And Philosophy: Surveillance State

December 30, 2013 by Marsh 78 Comments

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If you don’t live under a rock (though you may want to now) you probably saw yesterday’s article from Spiegel that revealed the NSA has its own catalog for spy gadgets. Today they released an interactive graphic with the catalog’s contents, and even if you’re not a regular reader of Hacking & Philosophy, you’re going to want to take a look at it. I recommend glancing over IRATEMONK, in the “Computer Hardware” category. As the article explains, IRATEMONK is

An implant hidden in the firmware of hard drives from manufacturers including Western Digital, Seagate, Maxtor and Samsung that replaces the Master Boot Record (MBR).

It isn’t clear whether the manufacturers are complicit in implanting IRATEMONK in their hardware, or if the NSA has just developed it to work with those drives. Either way, it raises an important question: how do we know we can trust the hardware? The short answer is that we can’t. According to the text accompanying the graphic, the NSA

…[installs] hardware units on a targeted computer by, for example, intercepting the device when it’s first being delivered to its intended recipient, a process the NSA calls ‘interdiction.’

We’re interested to hear your responses to this: is the situation as bleak as it seems? How do you build a system that you know you can trust? Are there any alternatives that better guarantee you aren’t being spied on? Read on for more.

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Hackaday Links: December 29, 2013

December 29, 2013 by Mike Szczys 6 Comments

There are a ton of cheap RF transceiver boards available. [Martin] recently took a look at several of the most common ones and reports back on what you want to look for when acquiring wireless hardware for your projects.

Ikea picture frame plus old laptop equals a roll-your-own digital picture frame which [Victor] built. It runs Ubuntu and is more powerful and extensible than anything you could purchase outright.

Our friend [HowToLou] sure loves the FlowRider. So much so that he’s trying to figure out how to make them less expensive to operate. He put together an example of how he thinks a standing wave can be created that follows the rider as they move along the surfing area.

[Garrett] released an Arduino library that offers threading, debugging, and error handling. The usertools package can be downloaded from his Github repository.

There’s only one way to gauge your Christmas cheer — hook yourself up to the XMeter built by [Geoff]. He’s the same guy who built a breathalyzer a couple of years back. It flashes images of holiday activities on a television while measuring galvanic response using a couple of DIY probes.

And finally, play around with a virtual x86 system. [Fabian Hemmer] wrote the incredibly full-featured virtual machine in JavaScript. You can get your hands on the code via his GitHub repo. [Thanks Martin]

Retrotechtacular: Submarine Cable Splicing Is Serious Business

December 24, 2013 by Kristina Panos 50 Comments

Really. As this wonderfully narrated talkie picture from 1939 will attest, keeping even one drop of water from penetrating undersea cables is of the utmost importance.

How do they do it? Many, many layers of protection, including several of jute wrapping. The video centers on splicing a new cable to an existing one in the San Francisco Bay to bring the wonder of telephony to a man-made island created for the Golden Gate International Expo.

The narrator makes these men out to be heroes, and when you see how much lead they came into contact with, you’ll understand what he means. Each of the 1,056 individually insulated wires must be spliced by hand. After that comes a boiling out process in which petrolatum is poured over the splice to remove all moisture. Then, a lead sleeve is pulled over the connections. Molten lead is poured over the sleeve and smoothed out by hand.

At this point, the splice is tested. The sleeve is punctured and nitrogen gas is pumped in at 20psi. Then comes the most important step: the entire sleeve is painted with soap suds. Any gas that escapes will make telltale bubbles.

Once they are satisfied with the integrity of the sheath, they wrap the whole thing in what appears to be lead cables and pound them into submission. Surely that would be enough, don’t you think? Nope. They weld the cables all around and then apply two coats of tar-treated jute wrapping, which retards saltwater corrosion considerably.

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3D Printering: Making A Thing In AutoCAD, Part II

December 22, 2013 by Brian Benchoff 18 Comments

It’s time once again for another part in 3D Printering’s series of Making A Thing. Last week was a short tutorial on the beginnings of making a thing in AutoCAD. This is an extremely complex software package, and in a desire to make things short and sweet, I broke this AutoCAD tutorial into two parts.

Since we already covered the 2D design portion of AutoCAD, part II of this tutorial is going to turn our 2D part into a three-dimensional object. Check out the rest of the tutorial below.

Continue reading “3D Printering: Making A Thing In AutoCAD, Part II” →

Hackaday Links: December 22, 2013

December 22, 2013 by Mike Szczys 7 Comments

[Korben] is using a picture frame as a Bluetooth speaker (translated). He hacked a Rock’R² for this project. It’s a device that has a vibrating element which can be used to make any hollow item into a speaker.

Entertain yourself over the holidays by mastering the Apollo Guidance Computer simulator. It’s a JavaScript version of the computer used in the modules of the Apollo moon missions. [Thanks Gregory and Paul]

Here’s a little mirror attachment that lets you use your laptop as an overhead projector. [Ian] calls it the ClipDraw. Affix it to the webcam and use the keyboard as the drawing surface. Since it’s simply using the camera this works for both live presentations and video conferencing. What we can’t figure out is why the image doesn’t end up backward?

This guide will let you turn a Carambola board into an AirPlay speaker.

Those who suck at remembering the rules for a game of pool will enjoy this offering. It’s some add-on hardware that uses a color sensor to detect when a ball is pocketed. The Raspberry Pi based system automatically scores each game.

We spend waaaay too much time sitting at the computer. If we had a treadmill perhaps we’d try building [Kirk’s] treadmill desk attachment. It’s made out of PVC and uses some altered reduction fittings to make the height adjustable. It looks like you lose a little bit of space at the front of the belt, but if you’re just using it at a walking pace that shouldn’t matter too much.

You can have your own pair of smart tweezers for just a few clams. [Tyler] added copper tape to some anti-static tweezers. The copper pads have wires soldered to them which terminate on the other end with some alligator clips. Clip them to your multimeter and you’ve got your own e-tweezers.