Farewell SETI@Home

March 6, 2020 by 59 Comments

It was about 21 years ago that Berkley started one of the first projects that would allow you to donate idle computing time to scientific research. In particular, your computer could help crunch data from radio telescopes looking for extraterrestrial life. Want to help? You may be too late. The project is going into hibernation while they focus on analyzing data already processed.

According to the home page:

We’re doing this for two reasons:

1) Scientifically, we’re at the point of diminishing returns; basically, we’ve analyzed all the data we need for now.

2) It’s a lot of work for us to manage the distributed processing of data. We need to focus on completing the back-end analysis of the results we already have, and writing this up in a scientific journal paper.

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Dumpster Finds Combined Into 4K Desktop Monitor

March 6, 2020 by 31 Comments

Dumpster diving is a time honored tradition in the hacking community. You can find all sorts of interesting hardware in the trash, and sometimes it’s even fully functional. But even the broken gadgets are worth taking back to your lair to strip for parts. If you’re as lucky as [Jamz], you might be able to mash a few devices together and turn them into something usable.

In this case, [Jamz] scored a LG 27UK650 monitor with a cracked display and a Dell OptiPlex 7440 “All-in-One” computer that was DOA. Separately these two pieces of gear were little more than a pile of spare parts waiting to be liberated. But if the control board could be salvaged from the monitor, and the working LCD pulled from the Dell…

After taking everything apart, [Jamz] made a frame for this new Frankenstein monitor using pieces of aluminum channel from the hardware store and 3D printed side panels. With the Dell LCD mounted in the skeletal frame, the control board from the LG monitor was bolted to the back and wired in. Finally the center section of the LG monitor’s back panel was cut out and mounted to the new hybrid display with a 3D printed frame.

Admittedly, these were some pretty solid finds as far as trash goes. You won’t always be so lucky. But if you can keep an open mind, the curb is littered with possibilities. How about some impressive home lighting that started life as a cracked flat screen TV?

Pump Up The (Windows) Volume With Physical Sliders

March 5, 2020 by 20 Comments

For as long as we can remember, Windows has provided a mixer that breaks out the volume level of every applicable application into its own slider-controlled lane. But navigating to these controls is non-trivial, especially if you’re in a hurry to silence someone on team speak. You have to stop what you’re doing, click the speaker, go into the mixer, and then go find the appropriate slider. Windows won’t respect resizes between mixer visits, so you’ll almost always have some horizontal scrolling to do.

So why on Earth would you put yourself through all of this when you could be pushing physical sliders on the fly like a DJ? A slider is just a potentiometer in a straight line, after all.

These are wired up to an Arduino Nano, which sends the serial data to a Python script on the PC that changes the volume values accordingly for whatever five programs are in the config file. Thanks to a little bit of Visual Basic, the Python script can run in the background.

[Aithorn]’s got everything you need to replicate this, so slide on over and grab the STL files and code. If you get to point where these sliders are too small, just build some bigger ones.

Brute-Forced Copyrighting: Liberating All The Melodies

March 5, 2020 by 23 Comments

Bluntly stated, music is in the end just applied physics. Harmony follows — depending on the genre — a more or less fixed set of rules, and there  are a limited amount of variation possible within the space of music itself. So there are technically only so many melodies possible, making it essentially a question of time until a songwriter or composer would come up with a certain sequence of notes without knowing that they’re not the first one to do so until the cease and desist letters start rolling in.

You might well argue that there is more to a song than just the melody — and you are absolutely right. However, current copyright laws and past court rulings may not care much about that. Aiming to point out these flaws in the laws, musician tech guy with a law degree [Damien Riehl] and musician software developer [Noah Rubin] got together to simply create every possible melody as MIDI files, releasing them under the Creative Commons Zero license. While their current list is limited to a few scales of fixed length, with the code available on GitHub, it’s really just a matter of brute-forcing literally every single possible melody.

Admittedly, such a list of melodies might not have too much practical use, but for [Damien] and [Noah] it’s anyway more about the legal and philosophical aspects: musicians shouldn’t worry about getting sued over a few overlapping notes. So while the list serves as a “safe set of melodies” they put in the public domain, their bigger goal is to mathematically point out the finite space of music that shouldn’t be copyrightable in the first place. And they definitely have a point — just imagine where music would be today if you could copyright and sue over chord progressions.
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Robotic Ball Bouncer Uses Machine Vision To Stay On Target

March 5, 2020 by 20 Comments

When we first caught a glimpse of this ball juggling platform, we were instantly hooked by its appearance. With its machined metal linkages and clear polycarbonate platform, its got an irresistibly industrial look. But as fetching as it may appear, it’s even cooler in action.

You may recognize the name [T-Kuhn] as well as sense the roots of the “Octo-Bouncer” from his previous juggling robot. That earlier version was especially impressive because it used microphones to listen to the pings and pongs of the ball bouncing off the platform and determine its location. This version went the optical feedback route, using a camera mounted under the platform to track the ball using OpenCV on a Windows machine. The platform linkages are made from 150 pieces of CNC’d aluminum, with each arm powered by a NEMA 17 stepper with a planetary gearbox. Motion control is via a Teensy, chosen for its blazing-fast clock speed which makes for smoother acceleration and deceleration profiles. Watch it in action from multiple angles in the video below.

Hats off to [T-Kuhn] for an excellent build and a mesmerizing device to watch. Both his jugglers do an excellent job of keeping the ball under control; his robotic ball-flinger is designed to throw the ball to the same spot every time.

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144 7-Segment Displays Combine To Form A Mighty Clock

March 5, 2020 by 25 Comments

What do you do with 144 7-segment displays? If you’re [Frugha] you put them all together to create an epic clock. Each display has 8 individual LEDs — 7 segments, and a decimal point. Put that all together, and you’ve got 1152 individual LEDs to control. This presented a problem, as [Frugha] wanted to control the clock with a single Arduino Nano. Even charlieplexing won’t get you that many I/O lines.

The solution was a nifty little chip called the MAX7219. The ‘7219 speaks SPI and can control 64 individual LEDs. [Frugha] used 18 of them in the clock, giving him full control over all his LEDs. That’s pretty impressive, considering the last matrix 7-segment display we saw required 48 Arduinos!

Another problem is memory – 1152 “pixels” would quickly overrun the 2KB RAM in the ATmega328. This is a clock though — which means only digits 0-9 and a colon. [Frugha] picked a nice font and hand-coded lookup tables for each digit. The lookup tables are stored in ROM, saving precious RAM on the Arduino.

A clock wouldn’t be any good if it wasn’t accurate. A Tiny RTC supplies battery-backed time data. [Frugha] wrapped everything up with a neat layout on a custom PCB. Sure, you could put it in a case, but we think a clock this crazy deserves to be left open – so you can see it in all its glory.

Debugging Electronics: To Know Why It Didn’t Work, First Find What It Is Actually Doing

March 5, 2020 by 10 Comments

Congratulations, you have just finished assembling your electronics project. After checking for obvious problems you apply power and… it didn’t do what you wanted. They almost never work on the first try, and thus we step into the world of electronics debugging with Daniel Samarin as our guide at Hackaday Superconference 2019. The newly published talk video embedded below.

Beginners venturing just beyond blinking LEDs and premade kits would benefit the most from information here, but there are tidbits useful for more experienced veterans as well. The emphasis is on understanding what is actually happening inside the circuit, which explains the title of the talk: Debugging Electronics: You Can’t Handle the Ground Truth! So we can compare observed behavior against designed intent. Without an accurate understanding, any attempted fix is doomed to failure.

To be come really good at this, you need to embrace the tools that are often found on a well stocked electronics bench. Daniel dives into the tricks of the trade that transcend printf and blinking LED to form a plan to approach any debugging task.

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