Retro DEF CON Badge Made From ’80s Parts

August 10, 2017 by John Baichtal 4 Comments

DEF CON 25’s theme was retro-tech, and [xres0nance] wasn’t kidding around in the retro badge he built for the convention. The badge was mostly built out of actual parts from the ’80s and ’90s, including the perfboard from Radio Shack—even the wire and solder. Of the whole project just the resistors and 555 were modern parts, and that’s only because [xres0nance] ran out of time.

[xres0nance] delayed working on the badge until his flight, throwing the parts in a box, and staggering to the airport in the midst of a “three-alarm hangover”. He designed the badge on the plane, downloading datasheets over in-flight WiFi and sketching out circuits in his notebook.

The display is from an old cell phone, and it uses a matrix of diodes to spell out DEFCON without the help of a microcontroller. Each letter is powered by a transistor, with specific pins blocked out to selectively power the segments. He used a shift register timed by a 555 to trigger each letter in turn, with the display scrolling the resulting message.

We publish a lot of posts about con badges. See our DEF CON 2015 badge summary for a bunch of badges that we encountered at in Vegas.

Hackaday Prize Best Product Finalist: Shape Shifting Structures For Space

August 10, 2017 by Steven Dufresne 20 Comments

While [Elon Musk] and [Jeff Bezos] are working on getting us to Mars and the Moon, [Ronald Jaramillo] is working on building structures once we get there. To that end, he’s been developing the ZBeam, two rolls of links that zip together like a zipper to form a rigid beam.

Initially stored in a compact cube targeted to eventually fit in a CubeSat’s dimension’s, 100 mm x 100 mm x 100 mm, the beam emerges from within the cube and will be able to connect with other cubes to form rigid structures. His hope is that they can one day be made automatically from lunar or Martian regolith (loose surface dirt) munching machines. His current one has 160 mm sides and uses a servo hacked to turn continuously.

In his hackaday.io project logs he shows the trial and error he’s gone through to get to his current stage: experimenting with the links to form a more rigid beam, fine tuning the unreeling of the rolls of links to prevent jamming, adding a safety-ratchet-gear to the gearing to overcome speed issues, and more. He currently 3D prints as many connected sets of links as he can on his Prusa i3, and then manually connects sets together to make a longer chain, but he has his eye on the Printrbot Printrbelt for printing arbitrarily long chains in one piece.

You can see one pretty impressive iteration of the ZBeam in action in the video below and more is on his project page. In fact, the judges for the 2017 Hackaday Prize liked [Ronald]’s projects so much that they designated it as a Best Product finalist.

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Getting Started With Blinking Lights On Old Iron

August 10, 2017 by Al Williams 29 Comments

If you ever go to a computer history museum, you’ll be struck by how bland most modern computers look. Prior to 1980 computers had lights and switches, and sometimes dials and meters. Some had switchboard-like wiring panels and some even had oscilloscope-like displays. There’s something about a machine with all those switches and lights and displays that gets your hacker juices flowing. Have you ever wanted to get started in retrocomputing? Is it difficult? Do you need a lot of money? That depends on what your goals are.

There are at least three ways you can go about participating in retrocomputing: You can pony up the money to buy actual antique computers, you can build or buy old computers recreated with anywhere from zero to one hundred percent of period-authentic components, or you can experiment with emulators that run on a modern computer. As a hybrid of the second and third option there are also emulations in FPGAs.

You can see that the first option can be very expensive and you will probably have to develop a lot of repair and restoration skills. Watching [Mattis Lind] twiddle the bits on an actual PDP-8 in the clip above is great, but you’ll need to work up to it. The two techniques which get you going without the original hardware don’t have to break the bank or even cost anything presuming you already have a PC.

Although some sneer at emulation, for some machines it is almost the only way to go. You couldn’t buy the original EDSAC, for example. It is also a good way to get started without a lot of expense or risk. But regardless of how you do it, there’s one thing in common: you have to know how to operate the thing.

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2017’s VCF West Is Another Beloved Trip Down Memory Lane

August 10, 2017 by Sonya Vasquez 20 Comments

This past weekend, another smashing round of the Vintage Computer Festival was held at the Computer History Museum in Mountainview. As always, VCF West gathers the sages and lords of vintage computers onto a common ground to talk old-school hardware. It also draws in a collection of unique artifacts, many of which either still work, have been brought back to life, or have otherwise been reincarnated through a modern means. [Bil Herd] and I dropped in to join the crowd, and I snagged a few pics of some new faces and pieces that have been added to the experience since last year.

[Foone’s] Digital Media Archiving

Up first on our bucket list was [Foone], a librarian of digital media archiving. Outside of VCF, he runs a digital media backup gig to help folks backup their niche, often-failing, disk formats into something more modern. His drive for doing this backup features a special “reread” capability, where the file is actually reread dozens of time to validate that the right information was pulled from it.

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CNC Mill Out Of A Building Set

August 10, 2017 by John Baichtal 19 Comments

I have some aluminum building-set parts on hand and just got a second rotary tool, so I thought I’d try my hand at making a light-duty CNC mill—maybe carve up some cheap pine or make circuit boards. This post explores some of the early decisions I’m facing as I begin the project.

Of primary importance is the basic format of the mill’s chassis. Gantry configuration or put everything in a box of girders? How will the axes move–belts or racks? How will the Z-axis work, the assembly that lowers the tool onto the material? Finally, once the chassis is complete, or perhaps beforehand, I’ll need to figure out how I intend to control the thing.

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Making A Cheap Radar Unit Awesome

August 10, 2017 by Elliot Williams 31 Comments

[JBeale] squeezed every last drop of performance from a $5 Doppler radar module, and the secrets of that success are half hardware, half firmware, and all hack.

On the hardware side, the first prototype radar horn was made out of cardboard with aluminum foil taped around it. With the concept proven, [JBeale] made a second horn out of thin copper-clad sheets, but reports that the performance is just about the same. The other hardware hack was simply to tack a wire on the radar module’s analog output and add a simple op-amp gain stage, which extended the sensing range well beyond the ten feet or so that these things are usually used for.

With all that signal coming in, [JBeale] separates out the noise by taking an FFT of the Doppler frequency-shift signal. Figuring that people walk around 2.2 miles per hour, [JBeale] focuses on the corresponding 70 Hz frequency bin and finds that the radar will detect people out to 80 feet. Wow!

This trick of taking an el-cheapo radar unit and amplifying the signal to do something useful isn’t new to Hackaday. [Mathieu] did it with the very same HB-100 unit way back in 2013, and then again with a more modern CDM324 model. But [JBeale]’s hacked horn and clever backend processing push out the limits of what you can expect to do with these cheap units. Kudos.

[via PJRC]

Convert Temperatures The Analog Way

August 10, 2017 by Dan Maloney 28 Comments

Everyone knows how to convert from Celsius to Fahrenheit, right? On a digital thermometer you just flick the little switch, on a weather app you change the settings, or if worse comes to worse, you let Google do the math for you. But what if you want to solve the problem the old-fashioned way? Then you pull out a few op amps and do your conversions analog style.

We’ve seen before how simple op amp circuits can do basic math, and the equation that [Kerry Wong] wants to solve is even simpler. Recalling the old T_f= 9/5·T_c + 32 formula (and putting aside the relative merits of metric versus traditional units; we’ve had enough of that argument already), [Kerry] walks us through a simple dual op amp circuit to convert the 1 mV/°C output of a thermocouple module to 1 mV/°F. The scaling is taken care of by a non-inverting amplifier with resistors chosen to provide a gain of 1.8, while the offset is handled by a differential amplifier that adds 32 mV to the scaled input. Strategically placed trimmers allow [Kerry] to tweak the circuit to give just the right conversion.

For jobs like this, it’s tempting to just use an analog input on an Arduino and take care of conversions in code. But it’s nice to know how to do it old school, too, and hats off to [Kerry] for showing us the details.

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