Demodulating BPSK31 With OpAmps And 555s

December 29, 2014 by Brian Benchoff 16 Comments

BPSK31 is an extremely popular mode for amateur radio operators; it’s efficient and has a narrow bandwidth and can be implemented with a computer sound card or an Arduino. Just like it says on the tin, it’s phase shift keying, and a proper implementation uses a phase detection circuit or something similar. [Craig] thought it would be fun to build an analog BPSK31 demodulator and hit upon the idea of doing this with amplitude demodulation. No, this isn’t the way you’re supposed to do it, but it works.

Data is transmitted via BPSK31 with a phase shift of 180 degrees being a binary 0, and no phase shift being a binary 1. [Craig]’s circuit uses an op-amp and a pair of diodes to do a full wave rectification of the signal, which basically makes a binary 1 logic high, and binary 0 logic low.

This rectified signal is then fed into a comparator, making the output go high when the signal is above 2V, and low when the signal is below 1V. That’s all you need to do to get bits out of the signal, all [Craig] had to do after that was figure out a way to sample it.

A 555 set up in astable mode running at 31.25 Hz provides the clock, synchronized with the signal by connecting the comparator’s output to the 555 trigger input. The timer clock ends up being slightly slower, but thanks to the varicode character set, the maximum number of binary ones the circuit will see is nine; every time the trigger sees a zero, the timer’s trigger is reset, re-synchronizing the receiver’s clock.

Yes, it’s a hack, and no, this isn’t how you’re supposed to receive PSK. It does, however, work, and you can thank [Craig] for that.

Ingenious Filament Spool Holder Keeps Your 3D Printer Printing

December 29, 2014 by James Hobson 16 Comments

If you have a 3D printer, chances are, the company you bought it from skimped out on the design of their filament holder. It’s okay though, it’s not like having a toilet roll holder for your spool will result in failed prints… oh wait…

We don’t normally share projects like this because, gasp, it’s not really a hack, but this completely 3D printed filament spool holder by [Creative Tools] is actually quite amazing. It’s been designed to fit pretty much any kind of spool of filament you can imagine, as well as no spool at all. But what impresses us most is how the entire thing is 3D printed or makes use of 3D printer filament. No fasteners, no nothing.

Stuff like using rubber filament instead of grippy foot pads, and hard filament as the axles with 3D printed wheels for the quasi-thrust bearing used to support and rotate the spool.

All the parts are available over at Thingiverse.com — even if you don’t have a 3D printer, you might want to see the following video for some inspiring design tips on how to make such a clean and polished 3D printed assembly.

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What Is The Matrix…Clock?

December 29, 2014 by Marsh 18 Comments

We’re surprised we haven’t seen this kind of clock before, or maybe we have, but forgot about it in the dark filing cabinets of our minds. The above picture of [danjhamer’s] Matrix Clock doesn’t quite do it justice, because this is a clock that doesn’t just tick away and idly update the minutes/hours.

Instead, a familiar Matrix-esque rain animation swoops in from above, exchanging old numbers for new. For the most part, the build is what you would expect: a 16×8 LED Matrix display driven by a TLC5920 LED driver, with an Arduino that uses a DS1307 RTC (real-time clock) with a coin cell battery to keep track of time when not powered through USB. [danjhamer] has also created a 3D-printed enclosure as well as added a piezo speaker to allow the clock to chime off customizable musical alarms.

You can find schematics and other details on his Hackaday.io project page, but first, swing down below the jump to see more of the clock’s simple but awesome animations.

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Project Binky, Putting A Celica In A Mini The Hard Way

December 28, 2014 by Brian Benchoff 48 Comments

The old Mini – not the new one, mind you – was a fantastic rally car, but fifty odd horsepower won’t get you very far today. The name of the game is souping up a pile of rust from 1980 to create one of the fastest Minis on the planet. That’s the goal of Bad Obsession Motorsport, a project by [Nik Blackhurst], [Richard Brunning], and [Rex Hamilton] as [Abraham Lincoln].

[Nik] has a 1980 Mini 1000, a car-shaped pile of rust. The plan for this multi-year build is to stuff the engine, gearbox, and suspension from a Toyota Celica ST185 GT4 into the old Mini. If you’re wondering, that’s a two liter, turbocharged engine with 200 horsepower and four-wheel drive in a Mini that originally had 50 or 60 horsepower. No, the engine doesn’t fit, but that’s not going to stop these guys.

This isn’t the kind of build you just dive into. Once the guys had the Mini in the garage, a load of measurements were taken from both cars, written down, and the car stripped down. This is not a simple mod, and a few pieces of equipment were custom-made just for this build. The biggest of these is a custom jig the Mini chassis can be bolted down to. This jig gives [Nik] and [Richard] the ability to mount the Mini and engine on rollers, and rotate the entire chassis 90 degrees for easy welding of the underside of the car.

Already there are eight videos covering a year and a half of work, and only now is there a light at the end of the tunnel. Most of the old body panels from the Mini were removed and replaced with reproduction parts. Those parts were quickly ruined with a cutting disk and some custom fabricated panels were put in place. Somehow, it still looks like a Mini but it’s massively strengthened and cut to accommodate the much larger suspension and engine from the Celica.

Grab a cup of coffee (or tea, if you’re into that) and check out the videos below. It’s incredible how much time and work went into this build, and we can’t wait to see the next update in a few months or so.

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College Researcher Makes Supercomputer From 420 PS3s

December 28, 2014 by Matt Freund 64 Comments

Noting that funding for science has run dry for many researchers, [Gaurav] has built a supercomputer from 200 Playstation 3 consoles housed and chilled inside an old refrigerated shipping trailer. His mission at UMass Dartmouth from the National Science Foundation is simulating black hole collisions with an eye on learning something about gravitational waves.

Dr. [Gaurav Khanna] is no stranger to using PS3 supercomputers to do meaningful science. Seven years ago he proposed a 16-PS3 supercomputer running Linux and managed to convince Sony to donate four consoles. The university kicked in funding for another 8 and [Gaurav] ponied up for the last four out of his own pocket. He dubbed it the “PS3 Gravity Grid” and received international attention for the cluster. For equivalent performance, it cost him only 10% the price of a real supercomputer. This led to published papers on both hacked supercomputers and gravity waves. But that rig is looking a little old today. Enter the Air Force.

Dr. [Khanna] was not the only one using PS3s to crunch data – back in 2010 the US Air Force built the “Condor Cluster” of 1,760 PS3s to perform radar imaging of entire cities and do neuromorphic AI research. With their hardware now expired, the Air Force donated 200 of the PS3s to [Gaurav] for his new build. Now that he has wired them up, the Air Force is donating another 220 for a not-snicker-proofed total of 420.

For those sceptical that the now 8-year-old hardware is still cost-effective, even with free consoles it is marginal. RAM is an issue and modern graphics cards are each equivalent to 20 PS3s. Ever the popular target these days, Sony has the PS4 OS locked down from the get go – thanks Sony. The next cluster planned will be with PCs and graphics cards. For now, [Gaurav] has plenty of calculations that need crunching and a queue of colleagues have formed behind him.

Hackaday Links: The Last One Of 2014

December 28, 2014 by Brian Benchoff 9 Comments

The guy behind the Microslice, a tiny Arduino-controlled laser cutter, has a new Kickstarter out. It’s called the Multibox PC, and it’s exactly what you need if you want to turn a Raspi, Banana Pi, HummingBoard, or Odroid U3 into an all-in-one desktop. 14″ 1366 x 768 LCD, and speakers turns dev boards into a respectable little Linux box.

If you’re learning to design schematics and lay out PCBs, you should really, really think about using KiCAD. It’s the future. However, Eagle is still popular and has many more tutorials. Here’s another. [Mushfiq] put together a series of tutorials for creating a library, designing a schematic, and doing the layout.

Another kickstarter wristwatch. But wait, this thing has a circular display. That’s really cool. It’s a 1.4″ 220×220 pixel, 262k color display. No, the display doesn’t use a polar coordinate system.

[Jari] wrote a digital logic simulator, Atanua, started selling licenses, and figured out it wasn’t worth developing on his own anymore. As promised, Atanua is now open source. If you want to look at the finances behind Atanua, here you go.

In 1970, you didn’t have a lot of options when it came to memory. One of the best options was Intel’s 1405 shift register – 512 bits of storage. Yes, shift registers as memory. [Ken Shirriff] got his hands on a memory board from a Datapoint 2200 terminal. Each of the display boards had 32 of these shift registers. Here’s what they look like on the inside

There’s a lot of talk about North Korean hackers, and a quick review of the yearly WordPress stats for Hackaday puts a tear in our eye. This year, there were fifty-four views from the Democratic People’s Republic of Korea. That’s just great. It’s awesome to see the hacker ethos make it to far-flung lands and through highly restricted firewalls. There’s still a long road ahead of us, though, and we’ll redouble our efforts on bringing the hacker mindset to Tuvalu and Saint Helena in the year 2015.

Pendulum Music For Oscilloscope And Photodiodes

December 28, 2014 by Elliot Williams 9 Comments

Two turntables and a microphone? Try two oscilloscopes and a couple of photodiodes. [dfiction] reinterpreted Steve Reich’s classic feedback piece for more modern electronics. The video is embedded after the break.

The original Pendulum Music is a conceptual musical composition from the heady year of 1968. Basically, you set a bunch of microphones swinging across speakers, making feedback as they pass by. The resulting rhythmic and tonal oscillations change over time as the swinging damps down. It’s either mesmerizing or entirely boring, depending on your mindset.

In the [dfiction] version, the feedback is produced by passing a “light microphone” over an oscilloscope. And since he’s got a pair of these setups, the one microphone also feeds the other ‘scope. The resulting sound is this chaotic and gritty noise-rumble. We dig it.

If slowly evolving “process music” pushes the boundaries of your attention span (or if it’s just not your thing) you can totally skip around in the video. Try around 1:40 and 3:45 into the piece just to get an idea of what’s going on. But once you’re there, you might as well let it run its course.

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