How A Dial-up Modem Handshake Works

January 31, 2013 by Mike Szczys 56 Comments

If you’re old enough to have used a dial-up modem we’d bet you can do an imitation of the sounds it made while connecting. Those not-so-beautiful sounds heralded the dawning of a technological era. But few actually know what each of those distinct sounds were doing. Now’s your chance to learn. This post explains each step in the dail-up handshake process.

This may be the most useful infographic we’ve ever seen. Normally we just seem them as gimmicks, but [Oona Räisänen] really put together something special with this one. Her blog post includes an audio clip so that you can play back the full handshake sounds. The main box on the graphic shows the audio spectrum from that clip, with an explanation below it. But you’ll also want to read through her full write-up for a more narrative description.

The part we found the most interesting is that these modems needed to disable the echo suppression used by the telephone system in order to operate at full-duplex. Apparently land lines disabled the speaker while you were talking so that you didn’t hear your own voice. This was a problem if the modem was trying to send and receive at the same time.

[via Reddit]

TV Show Inspires This Smaller Pong Paddles Hardware Hack

January 28, 2013 by Mike Szczys 8 Comments

smaller-pong-paddles

When we read “smaller paddles” we immediately thought of the physical controllers that you hold in your hands. But this hack alters the size of the virtual Pong paddles displayed on the TV screen.

We remember quite well the episode of That 70’s Show where Red and Kelso take apart their Pong machine to hack it. The video after the break which [Blues Image] put together shuffles scenes from that episode in with images of his hack. The characters are adamant that the game is too easy and reducing the size of the virtual paddles is the only thing that will make it fun again. After building his own hardware from the original schematics, [Blue Image] figured this challenge was worth a try.

His solution is in the form of two man-in-the-middle boards which insert a way to reroute the pins without altering the main board. One of the chips is used to draw the paddles, the other checks for collisions with the ball. By changing the pin-out the paddles are reduced from fifteen pixels down to seven.

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3D Printing Vacuum Tube Sockets

January 15, 2013 by Brian Benchoff 21 Comments

tubes

With the popularity of 3D printers and the current cult of vacuum tubes, it’s shocking we haven’t seen someone do this before.

[Peter] printed his own sockets for a few vacuum tubes he had lying around. After designing them on his computer, [Peter] printed them out on his local hackerspace’s 3D printer.

After printing out the plastic parts, [Peter] needed to add a few strips of metal for a conductor. He used a few pieces of an ATX power supply; a little difficult to fit, but something that works all the same.

So far, [Peter] has whipped up a few sockets for UX5 and VT76 tubes, UX6, B7G (7 pin mini), and B9D Magnoval tubes. No Nixie sockets yet, but it’s enough diversity to build your own tube amp using the most common designs. Now if we could only make our own transformers with laser cutters and 3D printers…

Magic Eye Spectrum Analyzer

January 14, 2013 by Brian Benchoff 13 Comments

its goddamned magic

If Nixies aren’t cool enough, maybe it’s time to step it up to magic eye tubes.

Magic eye tubes are, like Nixies and Dekatrons, display tubes. Unlike the alphanumeric characters of Nixies or rotating points of light in a Dekatron, Magic eye tubes are either bar graph or ‘Pac-Man’ displays that were used to show the signal strength of a radio station on very expensive radio sets.

After doing a few experiments with tubes, [sylvain] thought it would be cool to do something with magic eye tubes. He sourced eight vertical ‘bar graph’ magic eye tubes and built an audio spectrum analyzer.

One of the more difficult things to do was to compute the power levels for each frequency band. There are a few graphic equalizer ICs available, but [sylvian] decided to go the old-school, harder way by putting an FFT algorithm on an ATMega624.

An impressive piece of work that would look amazing next to a nice tube stereo system.

Hackaday Retro Roundup: Ultraportables Edition

January 12, 2013 by Brian Benchoff 17 Comments

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A few months ago, we rolled out an updated Hackaday, a badly needed new layout replacing the HTML and CSS that had remained unchanged since 2004. Of course a few people didn’t like change and complained about slow load times. We’ve experienced a slightly slower load time as well, so we’ll just wait until the year 2020 when our computers are many times faster and our Internet is provided by Google Fiber. Until then, our pokey battlestations and vintage computers can still check out a few classic hacks on our retro site. Here’s a few retro successes – Hackaday readers who pulled out their old tech and loaded up the retro site – that have come in over the past weeks and months.

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A Really, Really Tiny Tube Amp

January 11, 2013 by Brian Benchoff 37 Comments

After building his first tube amp from a kit, he set to work on his next amp build. Since tube amps are a much more experimental endeavor than their solid state brethren, [Jarek] decided to make his next amp unique with military surplus subminiature tubes, and in the process created the smallest tube amp we’ve ever seen.

Instead of bulky 12AX7s and EL34s tubes usually found in tube amp build, [Jarek] stumbled upon the subminiature dual triode 6021 tube, originally designed for ballistic missiles, military avionics, and most likely some equipment still classified to this day. These tubes not only reduced the size of the circuit; compared to larger amps, this tiny amplifier sips power.

The 100+ Volts required to get the tubes working is provided by a switched mode power supply, again keeping the size of the final project down. The results are awesome, as heard in the video after the break. There’s still a little hum coming from the amp, but this really is a fabulous piece of work made even more awesome through the use of very tiny tubes.

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In-depth Look At An LVCD Board From A Saturn V Rocket

January 9, 2013 by Mike Szczys 58 Comments

saturn-v-lvdc-board

Join [Fran] as she dons the hat of an electronics archaeologist when looking at this vintage circuit board from the space race. As part of her personal collection she somehow acquired a Launch Vehicle Digital Computer board for a Saturn V rocket. This particular unit was never used. But it would have been had the Apollo program continued.

[Fran] is enamored with this particular board because she believes it is the forerunner of modern digital circuit design and layout. Since routing circuit boards is part of what she does for a living you can see why this is important to her. Also, who isn’t excited by actual hardware from the space program? We’ve embedded two of her videos after the break. In the first she shows off the component to the camera and speaks briefly about it. But the second video has her heading to the dentist’s office for X-rays. The image above is a rotating X-ray machine, but it looks like the best imagery comes when a handheld gun is used. They get some great images of the traces, as well as the TTL components on the board itself.

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