Building A Semiautomatic Swag Launcher

February 15, 2019 by 4 Comments

Regular readers of Hackaday have certainly seen the work of [Jeremy Cook] at this point. Whether you remember him from his time as a writer for this fine online publication, or recognize the name from one of his impressive builds over the last few years, he’s a bona fide celebrity around these parts. In fact, he’s so mobbed with fans at events that he’s been forced to employ a robotic companion to handle distributing his personalized buttons for his own safety.

Alright, that might be something of a stretch. But [Jeremy] figured it couldn’t hurt to have an interesting piece of hardware handing out his swag at the recent Palm Bay Mini Maker Faire. Anyone can just put some stickers and buttons in a bowl on a table, but that’s hardly the hacker way. In the video after the break, he walks viewers through the design and construction of this fun gadget, which takes a couple unexpected turns and has contains more than a few useful tips which are worth the cost of admission alone.

Outwardly the 3D printed design is simple enough, and reminds us of those track kits for Matchbox cars. As you might expect, getting the buttons to slide down a printed track was easy enough. Especially when [Jeremy] filed the inside smooth to really get them moving. But the goal was to have a single button get dispensed each time the device was triggered, but that ended up being easier said than done.

The first attempt used magnets actuated by two servos, one to drop the button and the other to hold up the ones queued above it. This worked fine…at first. But [Jeremy] eventually found that as he stacked more buttons up in the track, the magnets weren’t strong enough to hold them back and they started “leaking”. This is an excellent example of how a system can work perfectly during initial testing, but break down once it hits the real world.

In this case, the solution ended up being relatively simple. [Jeremy] kept the two servos controlled by an Arduino and a capacitive sensor, but replaced the magnets with physical levers. The principle is the same, but now the system is strong enough to hold back the combined weight of the buttons in the chute. It did require him to cut into the track after it had already been assembled, but we can’t blame him for not wanting to start over.

Just like the arcade inspired candy dispenser, coming up with a unique way of handing out objects to passerby is an excellent way to turn the ordinary into a memorable event. Maybe for the next iteration he can make it so getting a button requires you to pass a hacker trivia test. Really make them work for it.

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In Space, No One Can Hear You Explode: The Byford Dolphin Incident

February 15, 2019 by 47 Comments

“It wouldn’t happen that way in real life.” One of the most annoying habits of people really into the “sci” of sci-fi is nitpicking scientific inaccuracies in movies. The truth is, some things just make movies better, even if they are wrong.

What would Star Wars be without the sounds of an epic battle in space where there should be no sound? But there are plenty of other examples where things are wrong and it would have been just as easy to get them right — the direction of space debris in the movie Gravity, for example. But what about the age-old trope of explosive decompression? Some movies show gross body parts flying everywhere. Others show distressed space travelers surviving in space for at least brief periods.

It turns out, dropping pressure from one atmosphere to near zero is not really good for you as you might expect. But it isn’t enough to just make you pop like some meat balloon. You are much more likely to die from a pulmonary embolism or simple suffocation. But you are a meat balloon if you experience a much greater change in pressure. How do we know? It isn’t theoretical. These things have happened in real life.

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Juicing Up The Chevy Volt With Raspberry Pi

February 15, 2019 by 31 Comments

While Chevrolet’s innovative electric hybrid might officially be headed to that great big junkyard in the sky, the Volt will still live on in the hearts and minds of hackers who’d rather compare amp hour than horsepower. For a relatively low cost, a used Volt offers the automotive hacker a fascinating platform for upgrades and experimentation. One such Volt owner is [Katie Stafford], who’s recently made some considerable headway on hacking her hybrid ride.

In an ongoing series on her blog, [Katie] is documenting her efforts to add new features and functions to her Volt. While she loves the car itself, her main complaint (though this is certainly not limited to the Volt) was the lack of tactile controls. Too many functions had to be done through the touch screen for her tastes, and she yearned for the days when you could actually turn a knob to control the air conditioning. So her first goal was to outfit her thoroughly modern car with a decidedly old school user interface.

Like most new cars, whether they run on lithium or liquefied dinosaurs, the Volt makes extensive use of CAN bus to do…well, pretty much everything. Back in the day it only took a pair of wire cutters and a handful of butt splice connectors to jack into a car’s accessory systems, but today it’s done in software by sniffing the CAN system and injecting your own data. Depending on whether you’re a grease or a code monkey, this is either a nightmare or a dream come true.

Luckily [Katie] is more of the latter, so with the help of her Macchina M2, she was able to watch the data on the CAN bus as she fiddled with the car’s environmental controls. Once she knew what data needed to be on the line to do things like turn on the fan or set the desired cabin temperature, she just needed a way to trigger it on her terms. To that end, she wired a couple of buttons and a rotary encoder to the GPIO pins of a Raspberry Pi, and wrote some code that associates the physical controls with their digital counterparts.

That’s all well and good when you need to mess around with the AC, but what’s the Pi supposed to do the rest of the time? [Katie] decided a small HDMI display mounted to the dash would be a perfect way for the Raspberry Pi to do double duty as information system showing everything from battery charge to coolant temperature. It also offers up a rudimentary menu system for vehicle modifications, and includes functions which she wanted quick access to but didn’t think were necessarily worth their own physical button.

In the video after the break, [Katie] walks the viewer through these modifications, as well as some of the other neat new features of her battery powered bow tie. What she’s already managed to accomplish without having to do much more than plug some electronics into the OBD-II port is very impressive, and we can’t wait to see where it goes from here.

Today there are simply too many good electric cars for hybrids like the Chevy Volt and its swankier cousin the Cadillac ELR to remain competitive. But thanks to hackers like [Katie], we’re confident this isn’t the last we’ve seen of this important milestone in automotive history.

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COB LED Teardown

February 15, 2019 by 15 Comments

[Big Clive] picked up some chip-on-board (COB) LEDs meant for hydroponics that were very unusual and set out to examine them on video. Despite damaging the board almost right away, he managed to do some testing on these arrays and you can see the results in the video below. He also compares it to older LED modules.

The 144 LEDs produce a lot of light. In addition to powering the device up, he also looks at the construction of the LEDs under a magnification, comparing the older style that used tiny bond wires to make connections versus the new version soldered on the board directly.

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Python Script Sends Each Speaker Its Own Sound File

February 14, 2019 by 8 Comments

When it comes to audio, the number of speakers you want is usually governed by the number of tracks or channels your signal has. One for mono, two for stereo, four for quadrophonic, five or more for surround sound and so on. But all of those speakers are essentially playing different tracks from a “single” audio signal. What if you wanted a single audio device to play eight different songs simultaneously, with each song being piped to its own speaker? That’s the job [Devon Bray] was tasked with by interdisciplinary artist [Sara Dittrich] for one of her “Giant Talking Ear” installation project. He built a device to play multiple sound files on multiple output devices using off the shelf hardware and software.

But maybe a hack like this could be useful in many applications other than just art installations. It could be used in an Escape room, where you may want the various audio streams to start in synchronicity at the same time, or as part of a DJ console, sending one stream to the speakers and another to the head phones, or a game where you have to run around a room full of speakers in the right sequence and speed to listen to a full sentence for clues.

His blog post lists links for the various pieces of hardware required, although all of it is pretty generic, and the github repository hosts the code. At the heart of the project is the Sounddevice library for python. The documentation for the library is sparse, so [Bray]’s instructions are handy. His code lets you “take a directory with .wav files named in numeric order and play them over USB sound devices attached to the host computer over and over forever, looping all files once the longest one finishes”. As a bonus, he shows how to load and play sound files automatically from an attached USB drive. This lets you swap out your playlist on the Raspberry Pi without having a use a keyboard/mouse, SSH or RDP.

Check the video after the break for a quick roundup of the project.

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FPGA Makes Digital Analog Computer

February 14, 2019 by 6 Comments

When you think of analog computing, it’s possible you don’t typically think of FPGAs. Sure, a few FPGAs will have specialized analog blocks, but usually they are digital devices. [Bruce Land] — a name well-known to Hackaday — has a post about building a digital differential analyzer using an FPGA and it is essentially an analog computer simulated on the digital fabric of an FPGA.

Whereas traditional analog computers use operational amplifiers to do mathematical integration, on the FPGA [Land] uses digital summers The devices simulate a system of differential equations, which can be nonlinear.

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Be Ready To Roll With Universal Electronic Dice

February 14, 2019 by 4 Comments

There are applications you can download for your smartphone that can “roll” an arbitrary number of dice with whatever number of sides you could possibly want. It’s faster and easier than throwing physical dice around, and you don’t have to worry about any of them rolling under the couch. No matter how you look at it, it’s really a task better performed by software than hardware. All that being said, there’s something undeniably appealing about the physical aspect of die rolling when playing a game.

Luckily, [Paul Klinger] thinks he has the solution to the problem. His design combines the flexibility of software number generation with the small form factor of a physical die. The end result is a tiny gadget that can emulate anything from a 2 to 64 sided die with just 6 LEDs while remaining as easy to operate as possible. No need to tap on your smartphone screen with Cheetos-stained hands when you’ve got to make an intelligence check, just squeeze the Universal Electronic Die and off you go. Granted you’ll need to do some binary math in your head, but if you’re the kind of person playing D&D with DIY electronic dice, we think you’ll probably be able to manage.

The 3D printed case that [Paul] came up with for his digital die is very clever, though it did take him awhile to nail it down. As shown in the video after the break, it took seven iterations before he got the various features such as the integrated button “flaps” right. There’s also a printed knob to go on the central potentiometer, to make it easier to select how many sides your virtual die will have.

In terms of the electronics, the design is actually quite simple. All that lives on the custom PCB is a ATtiny1614 microcontroller, the aforementioned LEDs, and a couple of passive components. A CR2032 coin cell powers the whole operation, and it should provide enough juice for plenty of games as it’s only turned on when the user is actively “rolling”.

We’ve seen a number of very impressive electronic dice projects over the years, and it doesn’t look like the trend is slowing down anytime soon. Of course, if you absolutely must hear those physical dice rolling, we can help you with that too.