Simple Fuel Pressure Alarm Averts Diesel Disaster

If you could spend a couple of bucks on a simple project that might prevent a $2000 repair bill on your vehicle, you’d probably build it, right? That’s the idea behind this simple low-pressure alarm for a diesel fuel system, and it’s so simple it makes you wonder why the OEM didn’t do it.

We normally see [Bob Johnson] coming up with nifty projects (like this claw or this camera slider) that more often than not combine woodworking and electronics. But no tree carcasses were harmed in the making of this project. [Bob]’s goal is just to sound a warning and flash a light if the output of a pressure switch goes to ground. That indicates the lift pump in his Dodge Ram’s fuel tank has failed, which could lead to the sudden failure of the downstream injector pump for lack of lubrication by the fuel itself. His simple ATtiny85 circuit lives on a small perfboard in a 3D printed case and taps into a $30 fuel pressure switch. The microcontroller code enables a short delay to prevent nuisance alarms, and if the pressure drops below 5 PSI, [Bob] gets a chance to shut down the engine and disappoint his mechanic to the tune of $2000.

Maybe it’s planned obsolescence on the OEM’s part, or maybe it’s not. But kudos to [Bob] for a simple hack that averts a potentially expensive problem.

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Meet Blue Jay, The Flying Drone Pet Butler

20 students of the Eindhoven University of Technology (TU/e) in the Netherlands share one vision of the future: the fully domesticated drone pet – a flying friend that helps you whenever you need it and in general, is very, very cute. Their drone “Blue Jay” is packed with sensors, has a strong claw for grabbing and carrying cargo, navigates autonomously indoors, and interacts with humans at eye level.

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How To Design, Manufacture, And Document A Hardware Product

It’s pretty awesome to have a hardware design hero jump at the chance to work on a Hackaday conference badge. I am of course talking about Voja Antonic.

I’ve gotten to know him over the last two years when we were introduced and he agreed to work on some original articles. He’s long been a hacker and shared his story of technology despite politics and society changing around him. His Galaksija computer was the first personal computer available in Yugoslavia with over 8,000 kits sold. Since those days he never stopped refining his design and fabrication skills. For instance, his method of making cases from FR4 is beyond compare, and reading some of his wisdom from hardware design in the casino industry is the kind of fascinating stuff that rarely makes it out for others to enjoy.

But I digress — the point is Voja’s been around the block, he knows what he’s doing, and he does it at an amazingly high level. He did an incredible job with the Hackaday | Belgrade conference badge. It features a 16×8 LED display, IR comms hardware, 5 user buttons, USB programming, an option for an accelerometer module, and has spectacular life running on two AAA batteries. It was a hit at the conference, and so was his talk discussing the design and fabrication. Check it out below and then join me below the fold.

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Hackaday Dictionary: Transformers

Funny stuff, electricity. It’s all about the volts and the amps, and controlling these two factors. Most of the time, the electricity coming into your device is at a higher voltage than you need, so you have to convert it down to something more usable. The easiest way to do this is with a transformer.

The transformer in your power supply takes a high voltage from the mains and converts it down into a lower voltage to power your gadgets. You’ll find one in all power supplies, from the miniature USB version that powers your cell phone to the big ones hanging on a telephone pole that drive your home’s mains electricity. Although these transformers are different sizes, they share the same fundamental design.

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Fallout Inspired Cellphone Wristwatch

[Mr. Volt] mentions that some of the commenters on his videos believed that he shouldn’t be making large, retro computer themed communicator watches. He believes they are wrong, naturally we are compelled to agree with him.

thrumbzIn his latest build he has produced a rather well-built and large cell-phone watch. After the untimely death of an Apple II cellphone watch, he decided to up his game and make one that could take more of a beating. The case is 3D printed, which is hard to believe given the good finish. He must have spent a long time sanding the prints. Some wood veneer for looks and aluminum panels for strength complete the assembly.

The electronics are a Teensy and a GSM module. It looks like he places calls by calling the operator since the wrist communicator only has four inputs: a red button, a blue button, and a momentary switch rotary encoder.

The communicator appears to work really smoothly, and it would certainly draw attention to him were he to wear it anywhere other than the Wasteland. Video after the break.

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Up Your CAD Game With Good Reference Photos

I’ve taken lots of reference photos for various projects. The first time, I remember suffering a lot and having to redo a model a few times before I got a picture that worked. Just like measuring parts badly, refining your reference photo skills will save you a lot of time and effort when trying to reproduce objects in CAD. Once you have a model of an object, it’s easy to design mating parts, to reproduce the original, or even for milling the original for precise alterations.

I’m adding some parts onto a cheap food dehydrator from the local import store. I’m not certain if my project will succeed, but it’s a good project to talk about taking reference photos. The object is white, indistinct, and awkward, which makes it a difficult object to take a good photo for reference use in a CAD program. I looked around for a decent tutorial on the subject, and only found one. Maybe my Google-fu wasn’t the best that day. Either way, It was mostly for taking good orthogonal shots, and not how to optimize the picture to get dimensions out of it later.

There are a few things to note when taking a reference photo. The first is the distortion and the setup of your equipment to combat it. The second is including reference scales and surfaces to assist in producing a final model from which geometry and dimensions can be accurately taken. The last is post-processing the picture to try to fight the distortion, and also to prepare it for use in cad and modeling software.

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3D Printing Hailstone Molds For Science

Hollywood would have you believe that tornadoes are prevalent in the Midwest. We’re much more likely to see hail in the springtime—balls of slushy ice that pelt our roofs and dimple our cars. [Dr. Ian Giammanco] and his wife and fellow scientist [Tanya Brown-Giammanco] have been studying hail at the Insurance Institute for Business and Home Safety’s research lab since 2012. In 2013, their team created over 9,000 artificial hailstones and fired them at a mock-up of  a house in the first indoor full-scale hailstorm.

As fun as it sounds to shoot balls of ice at different things, they did it to better understand the humble hailstone and the damage it can do to insurable goods. Those hailstones from a few years ago were created manually by injecting molds and freezing them. Recently, [the Giammancos] and  have taken a more advanced approach to creating artificial hail so they can study the physical characteristics. They scan actual hailstones in order to create models of them. Then they make a 3D-printed mold and use it in a hail-making machine that uses diffused carbon dioxide to mimic the layering that occurs when natural hailstones are formed.

While it would be nice to be able to control hail, the next best thing is mitigating the damage it causes. The better that scientists understand hail, the better materials will become that can withstand its impact. Perhaps someone can perfect a shape-shifting building material and make it resistant to hail.