Guardin, Guarding The Garden: Turn Raspberry Pi Into A 3rd Eye

August 23, 2018 by 16 Comments

If you are a gardener, you’ll know only too well the distress of seeing your hard work turned into a free lunch for passing herbivorous wildlife. It’s something that has evidently vexed [Jim], because he’s come up with an automated Raspberry Pi-controlled turret to seek out invading deer, and in his words: “Persuade them to munch elsewhere”.

Before you groan and sigh that here’s yet another pan and tilt camera, let us reassure you that this one is a little bit special. For a start, it rotates upon a set of slip rings rather than an untidy mess of twisted cables, so it can perfom 360 degree rotations at will, then it has a rather well-designed tilting cage for its payload. The write-up is rather functional but worth persevering with, and he’s posted a YouTube video that we’ve placed below the break.

This is a project that still has some way to go, for example just how those pesky deer are to be sent packing isn’t made entirely clear, but we think it already shows enough potential to be worthy of a second look. The slip ring mechanism in particular could find a home in many other projects.

It’s worth reminding readers that while pan and tilt mechanisms can be as impressive as this one, sometimes they are a little more basic.

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The First Vending Machine Hacked Liquor Laws: The Puss And Mew

August 23, 2018 by 37 Comments

It is fair to say that many technologies have been influenced by human vices. What you may not realize is that vending machines saw their dawn in this way, the first vending machine was created to serve booze. Specifically, it was created to serve gin, the tipple of choice of the early 18th century. it was created as a hack to get around a law that made it harder to sell alcoholic drinks. It was the first ever vending machine: the Puss and Mew.

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Marines 3D-Print Part To Repair Multi-Million Dollar Fighter

August 23, 2018 by 71 Comments

The good news: all you need to complete the repair you’re working on is one small part. The bad news: it’s only available in a larger, expensive assembly. The worst news: shipping time is forever. We’ve all been there, and it’s a hard pill to swallow for the DIYer. Seems like a good use case for 3D-printing.

Now imagine you’re a US Marine, and instead of fixing a dishwasher or TV remote, you’ve got a $123 million F-35 fighter in the shop. The part you need is a small plastic bumper for the landing gear door, but it’s only available as part of the whole door assembly, which costs $70,000 taxpayer dollars. And lead time to get it shipped from the States is measured in weeks. Can you even entertain the notion of 3D-printing a replacement? It turns out you can, and it looks like there will be more additive manufacturing to come in Corps repair depots around the world.

Details of the printed part are not forthcoming for obvious reasons, but the part was modeled in Blender and printed in PETG on what appears to be a consumer-grade printer. The part was installed after a quick approval for airworthiness, and the grounded fighter was back in service within days. It’s encouraging that this is not a one-off; other parts have been approved for flight use by the Marines, and a whole catalog of printable parts for ground vehicles is available too. This is the reality that the 3D printing fiction of Lost in Space builds upon.

And who knows? Maybe there are field-printable parts in the disposable drones the Corps is using for standoff resupply missions.

[via 3D-Printing Industry]

Memristor May Be Fake News

August 23, 2018 by 31 Comments

The fundamental passive components of electronics are the resistor, the capacitor, the inductor, and the oscillator, right? Actually, no, oscillators aren’t considered fundamental components because they aren’t linear. Resistors, capacitors, and inductors are also irreducible. That is, you can’t combine other passive components to model them unlike, say, a potentiometer. In the last few decades, though, we’ve heard of another fundamental component — the memristor. [Isaac Abraham] asserts, though, that the memristor isn’t a new fundamental component, but just an active device.

To support that premise [Isaac] builds a periodic table of devices showing how components map to changing voltages based on the time-varying property of charge. This shows that all the basic relationships are filled and that memristor actually covers a composition of passive components. This is similar in concept to [Strukov’s] diagram implying that a memristor is the fourth quadrant of a space defined by charge vs flux. However, using the properties of this periodic table [Isaac] argues against the fundamental nature of the memristor.

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Toil In Style With Salvaged Porsche Office Chairs

August 22, 2018 by 22 Comments

It seems as if everyone has finally decided to stop pretending that standing in front of a desk for 8+ hours was something anyone actually wanted to do, and once again embrace the classic adjustable office chair. But whether you’re writing code in a cubicle or are one of those people who apparently makes a living by having people watch them play video games, one thing is certain: your chair needs to be cool enough to make up for the years shaved off your life by sitting in it all day.

Case in point, these chairs that were made out of seats salvaged from a Porsche 996 by [Colby Newman]. You might never be able to afford the car they came out of on your salary, but at least you can pretend you’re power shifting into fifth while doing your TPS reports.

The first step, and arguably the most important one, was getting the seats from a Porsche. [Colby] wisely cautions the reader that they should avoid seats with air bags, as the last thing you want is your chair to explode while you’re streaming Fortnite. This is especially true if you are looking to salvage the seats yourself from the junkyard, as special care needs to be taken on how you remove them from the vehicle.

Assuming you got the seat without blowing yourself up, the next step is to mate it to the adjustable base. This part is going to depend on the make and model of vehicle you got the seats out of, but in this case it was fairly easy to use some flat steel bars to adapt the tubular frame of the Porsche’s seat to the base from the donor office chair. [Colby] put everything together with nuts and bolts, but this could potentially be an excuse to drag out the welder.

We’ve previously seen the driver seat salvaged from a wrecked car for use in a simulator, and a standard office chair upgraded with force feedback. We wonder who will be the first to combine all these ideas into one ultimate office racing chair…

Cross-Correlation Makes Quick Work Of Ads

August 22, 2018 by 25 Comments

Once relegated to the proverbial Linux loving Firefox user, ad blocking has moved into public view among increased awareness of privacy and the mechanisms of advertising on the internet. At the annual family gathering, when That Relative asks how to setup their new laptop, we struggle through a dissertation on the value of ad blockers and convince them to install one. But what about mediums besides the internet? Decades ago Tivo gave us one button to jump through recorded TV. How about the radio? If available, satellite radio may be free of The Hated Advertisement. But terrestrial radio and online streams? [tomek] wasn’t satisfied with an otherwise sublime experience listening streaming Polish Radio Three and decided to build a desktop tool to detect and elide ads from the live audio stream.

[tomek] was aware of this hip knowledge domain called Digital Signal Processing but hadn’t done any of it themselves. Like many algorithmic problems the first step was to figure out the fastest way to bolt together a prototype to prove a given technique worked. We were as surprised as [tomek] by how simple this turned out to be. Fundamentally it required a single function – cross-correlation – to measure the similarity of two data samples (audio files in this case). And it turns out that Octave provides it in the box. After snipping the start-of-ad jingle out of a sample file and comparing it to a radio program [tomek] got the graph at the left. The conspicuous spike is the location of the jingle in the audio file.

At this point all that was left was packaging it all into a one click tool to listen to the radio without loading an entire analysis package. Conveniently Octave is open source software, so [tomek] was able to dig through its sources until they found the bones of the critical xcorr() function. [tomek] adapted their code to pour the audio into a circular buffer in order to use an existing Java FFT library, and the magic was done. Piping the stream out of ffmpeg and into the ad detector yielded events when the given ad jingle samples were detected.

[tomek] packaged that tool into a standalone executable, but the gem here is the followup post. After removing ads in the online stream they adapted a RaspberryPi to listen to an FM receiver and remote control their Yamaha tuner over the network. So when the tuner is playing Radio Three the Pi notices and ducks the audio appropriately to avoid those pesky ads. Video of this after the break.

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An Incredible ATX Amiga 4000 Motherboard

August 22, 2018 by 18 Comments

No matter how far modern computer hardware advances, there’s still a fairly large group of people who yearn for the early days of desktop computing. There’s something undeniably appealing about these early systems, and while even the most hardcore vintage computer aficionado probably wouldn’t be using one as their daily computer anymore, it’s nice to be able to revisit them occasionally. Of course the downside of working with computers that may well be older than their operators is that they are often fragile, and replacement parts are not necessarily easy to come by.

But thanks to projects like this impressive ATX Amiga 4000 motherboard shown off by [hese] on the Amibay forums, getting first hand experience with classic computing doesn’t necessarily mean relying on vintage hardware. By making an Amiga that’s compatible with standard ATX computer cases and power supplies, it becomes a bit more practical to relive the Commodore glory days. Right now it’s mainly a personal project, but if there’s sufficient interest it sounds as if that might change.

This board could be considered a modern reincarnation of the Amiga 4000T, which was an official tower version of the standard Amiga 4000 released by Commodore in 1994. It features a 68030 CPU, with 16 MB Fast RAM and 2 MB Chip RAM. For expansion there are four full-length Zorro III slots and three ISA slots, as well as IDE ports for a floppy and hard drive.

The board really looks the part of a professionally manufactured computer motherboard from the late 1990s, which speaks not only to the attention to detail [hese] put into its design, but the manufacturing capabilities that are now available to the individual. With passionate people like this involved, it’s hardly surprising that the vintage computer scene is so vibrant.

Of course, this isn’t the first newly built “vintage” computer we’ve seen here at Hackaday. From bare-minimum 8085 computers to the comparative luxury of the 6502-powered Cactus, it seems like what’s old is new again.

[Thanks to Laurens for the tip.]