This Saturday: Meetup With Hackaday, Tindie, And Kickstarter

May 15, 2019 by 2 Comments

If you’re near San Francisco this weekend, this is what you should be doing. It’s The 6th Annual Hackaday x Tindie MFBA Meetup w/ Kickstarter.

Come hang out with the hardware hackers and bring along a project of your own to get the conversation going. We’re excited to move to a new, larger venue this year. All the good of the past five years will come along with us, plus many benefits of exclusively booking out an entire venue. You can catch up with people who have been on their feet all day running booths — and usually see the stuff they can’t show you at the Faire. The crew from Hackaday, Tindie, and Kickstarter will be on hand. And you’ll get a glimpse of a lot of the cool people and projects you’ve admired on the pages of Hackaday over the years. It’s fun, you should go!

First beer is on us if you RSVP using the link at the top of this article. But we’re mainly publishing this today to show off the poster art. Deposit your adoration for this exquisite illustration in the comments below.

Amazing Art by Joe Kim

We love all of the original art that Joe Kim creates for Hackaday articles. It’s impossible to look at his poster for this event and be anything but overjoyed. Here’s a link to the full size image, but be warned that the file is 14.4 MB

Emotigun Sends A Stinging Message

May 15, 2019 by 11 Comments

Emojis, the graphical descendants of textual emoticons, are everywhere these days. They’re commonly used on social media platforms as a way of indicating a basic emotional response to a post. That wasn’t enough for [Tadas Maksimovas], who built the Emotigun to really get the point across.

Fundamentally, the Emotigun is akin to a Gatling cannon for small foam emojis. Firing over ten rounds per second, it’s built primarily out of wood, using Precise anti-cold rubber bands to fling its ammunition at targets. This was a practical choice, as the original Thera-Band green rubber tubes became inelastic in the cold temperatures of the testing environment. The finer details of the build are laid out in a document for those eager to know more.

The build was a team effort, with many pitching in, and even [Jorg Sprave] lending his expertise to the build. Given [Jorg]’s expertise, we’re not surprised the final result is so impressive. Reports are that filming the machine in action was quite an ordeal, with [Tadas] taking over 200 rounds to the face during the course of the shoot. Video after the break.

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The Great Ohio Key Fob Mystery, Or “Honey, I Jammed The Neighborhood!”

May 15, 2019 by 91 Comments

Hack long enough and hard enough, and it’s a pretty safe bet that you’ll eventually cause unintentional RF emissions. Most of us will likely have our regulatory transgression go unnoticed. But for one unlucky hacker in Ohio, a simple project ended up with a knock at the door by local authorities and pointed questions to determine why key fobs and garage door remotes in his neighborhood and beyond had suddenly been rendered useless, and why his house seemed to be at the center of the disturbance.

Few of us want this level of scrutiny for our projects, so let’s take a more in-depth look at the Great Ohio Key Fob Mystery, along with a look at the Federal Communications Commission regulations that govern what you can and cannot do on the airwaves. As it turns out, it’s easy to break the law, and it’s easy to get caught.

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Comprinter Hides A Laptop Inside A Printer

May 15, 2019 by 13 Comments

Sometimes we find projects that border on the absurd but are too cool to pass up. The Comprinter is exactly that. [Mason Stooksbury] had a dream. An all-in-one scanner printer that was also a computer. What would turn heads more than walking into a hackerspace with a printer, plugging your headphones in, then opening up the top to reveal a monitor?

[Mason’s] dream became possible when friends gave him some old laptops and a dead Kodak printer. After going through the laptops, he picked a Dell Inspiron 1440 to be the donor machine. The printer and laptop were both carefully stripped down. [Mason’s] goal for the project was to build a “beautiful” printer/computer. No bodges allowed. He spent most of his time planning out how to mount the motherboard and display inside the scanner section of the chassis.

The actual assembly was quite fiddly. Working with only an inch or so of clearance, [Mason] installed standoffs for the motherboard and display. He to do all this without breaking the wires for the display and WiFi antennas.

Once the main parts of the laptop were assembled, [Mason] completed the build with a nine-port USB hub, some internally mounted speakers and a USB keyboard mounted in the paper tray. The twelve-hour operation was a complete success. What looks to be a cheap inkjet actually hides a complete laptop running Xubuntu. The only downside is that the printer doesn’t actually print, but [Mason] is quick to note that if the printer hadn’t been broken in the first place, it would work fine — all the modifications are in the scanner section.

We’ve seen some wild casemods over the years, including a Nintendo in a toaster, a modern PC stuffed into an original Xbox, and Raspberry Pi’s stuffed into just about everything.

Microscope-Inspired Toolchanger Spins Multicolor 3D Prints

May 15, 2019 by 15 Comments

The 3D printing community is simply stirring with excitement over toolchanging printers, but these machines are still the exception rather than the norm. Here’s an exceptional exception: [Paul Paukstelis] built a five-color printer with a novel head-changing solution.

[Paul’s] 3D printer is a hat-tip to anyone who’s spent time in the wetlab. For starters, the printer is born from the remains of a former liquid handling system, a mighty surplus score. When it comes to headchanging, [Paul] combined some honest inspiration from E3D’s toolchanging videos with some design features borrowed from the microscope in his lab. The result is that the printer’s five-tool head-changer mechanically behaves very similarly to the nose piece in a compound light microscope.

Because the printer evolved from old lab equipment, [Paul] dubs his printer into a lineage that he calls the “Reclaimed Rapid-Prototyper,” or the RecRap. Best of all, he’s kindly posted up the CAD files on the Thingiverse such that you too can take a deep look into this head-changing solution.

We love seeing these tools get a second life, and we think there’s plenty of potential for new offspring in this lineage of discarded lab equipment.

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Deflecting Earthquakes The Way Ancient Romans Did It

May 14, 2019 by 27 Comments

A recent French study indicates that the ancient Romans may have figured out how to deal with earthquakes by simply deflecting the energy of the waves using structures that resemble metamaterials. These are materials which can manipulate waves (electromagnetic or otherwise) in ways which are normally deemed impossible, such as guiding light around an object using a special pattern.

In a 2012 study, the same researchers found that a pattern of 5 meter deep bore holes in the ground was effective at deflecting a significant part of artificially generated acoustic waves. One of the researchers, [Stéphane Brûlé], noticed on an aerial photograph of a Gallo-Roman theater near the town of Autun in central France that its pattern of pillars bore an uncanny resemblance to this earlier experiment: a series of concentric (semi) circles with the distance between the pillars (or holes) decreasing nearer the center.

Further research using archaeological data of this theater site confirmed that it did appear to match up the expected pattern if one would have aimed to design a structure that could successfully deflect the acoustic energy from an earthquake. This raises the interesting question of whether this was a deliberate design choice, or just coincidence.

Additional research on the Colosseum in Rome and various other amphitheaters did however turn up the same pattern, which makes it seem like a deliberate choice by the Roman builders over a long period of time. With this pattern apparently capable of protecting a structure from the destructive effects of the acoustic waves generated by an earthquake, the remaining question is whether they discovered this pattern over time by observing damage to buildings and decided to implement it in new buildings.

Although we’ll likely never get an answer to that question, this discovery can however lead to improvements to individual buildings today, as well as entire cities, that may protect them against earthquakes and save countless lives that way.

The Kalman Filter Exposed

May 14, 2019 by 10 Comments

If we are hiring someone such as a carpenter or an auto mechanic, we always look for two things: what kind of tools they have and what they do when things go wrong. For many types of embedded systems, one important tool that serious developers use is the Kalman filter. It is also something you use when things go “wrong.” [Carcano] recently posted a tutorial on Kalman filter equations that tries to demystify the topic. His example — a case of things going wrong — is when you have a robot that knows how far it is supposed to move and also has GPS coordinates of its positions. Since the positions probably don’t agree, you can consider that a problem with the system.

The obvious answer is to average the two positions. That’s fine if the error is small. But a Kalman filter is much more robust in more situations. [Carcano] does a good job of taking you through the math, but we will warn you it is plenty of math. If you don’t know what a Gaussian distribution is or the word covariance makes you think of sailboats, you are going to have to do some reading to get through the post.

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