misc hacks

Embiggen your Eclipse 2017 Experience with a Sun Funnel

August 19, 2017 by 1 Comment

As exciting as Eclipse 2017 is going to be this Monday, for some folks it might appear a bit — underwhelming. Our star only occupies about half a degree of the sky, and looking at the partial phase with eclipse glasses might leave you yearning for a bigger image. If that’s you, you’ll need to build a sun funnel for super-sized eclipse fun.

[Grady] at Practical Engineering is not going to be lucky enough to be within the path of totality, but he is going to be watching the eclipse with a bunch of school kids. Rather than just outfitting his telescope with a filter and having the kids queue up for a quick peek, he built what amounts to a projection screen for the telescope’s eyepiece. It’s just a long funnel, and while [Grady] chose aluminum and rivets, almost any light, stiff material will do. He provides a formula for figuring out how long the funnel needs to be for your scope, along with plans for laying out the funnel. We have to take exception with his choice of screen material — it seems like the texture of the translucent shower curtain might interfere with the image a bit. But still, the results look pretty good in the video below.

Eclipse 2017 is almost here! How are you planning to enjoy this celestial alignment? By proving Einstein right? By studying radio propagation changes? Or just by wearing a box on your head? Sound off in the comments.

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Fool Giants with Novelty-Sized Gold Bricks

August 18, 2017 by 19 Comments

If you ever wondered how to make a giant-sized gold bar out of sheets of pink household insulation, well, there is a video showing you the steps. YouTube workshop guru [Jimmy DiResta] built oversized prop gold bricks out of foam. He cut sheets of 1.5″ Owens Corning foam insulation on his Saw Stop, making angled edges onto each piece so they could fit together in the trapezoidal ingot shape we know and love.

The pieces were put together with Great Stuff insulating foam sealant, the sort of spray foam used for filling up gaps in your house’s insulation, but here serving as glue.  [Jimmy] created lettering by lasering out the shapes in what appears to be cardboard, then gluing the letters in place, using the leftover material from the laser cut to place the letters in neat rows. He then sanded down the edges, priming and painting the bars with gold paint–but there were too many imperfections visible so he re-sanded and repainted.

We have been inundated in foam projects recently, like this ultralight built out of foam insulation and a foam cutter built with a 9V battery.

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Catch the Eclipse with a Wearable Pinhole Camera

August 18, 2017 by 15 Comments

You say you didn’t have enough warning to order eclipse glasses, and now they’re too expensive to buy? Or maybe you did order some but they ended up being those retina-combusting knock-offs, and now you’ve got nothing to protect you during the partial phase of Monday’s eclipse? Don’t dump a ton of money on unobtainium glasses — just stick your head in a cardboard box.

You may end up looking like a Box Troll with the aptly named [audreyobscura]’s box on your head, but it really is a safe and effective way of watching the eclipse, or for gazing at our star anytime for that matter. It’s nothing more than a large pinhole camera, with a tiny hole in a scrap of aluminum soda can acting as an aperture. The pinhole in one end of a box casts a perfect image of the sun on a paper screen at the other end of the box. A hole for your head with a proper gasket around your neck — maybe the neck of an old T-shirt would be a bit more comfortable and light tight? — and you’re ready for the show. The bigger the box, the bigger (and dimmer) the image will be, so you’ll want to cruise the local home center for long boxes. Because walking around with a water heater box on your head is totally cool.

Really, though, Hackaday readers can’t say they didn’t know this was coming. We started covering this in January, we’ve got hundreds of eclipse meetups across the country, and we’ve even covered some citizen science opportunities you can partake in on Eclipse Day. If you don’t have your head in a box, that is.

Thanks to [Roger Guess] for the idea on this one.

Wield The Power of Molten Metal

August 16, 2017 by 16 Comments

[TheBackyardScientist] at it again with another super villain-esque demonstration of gadgetry: a liquid metal squirt gun.

The squirt gun has a compressed air tank like most others — more on that later — but to fire its primary ammunition, a nozzle that connects directly to an air compressor is needed. Again, like most guns of this nature, air is forced into the gun’s reservoir, displacing the pewter and expelling it out the gun’s barrel. Yes, pewter.

Working around the heat tolerances of thread seal tape, pewter has a low enough melting point that an airtight system is preserved — plus it’s really cool to fire a stream of liquid metal. The ammunition is made from pewter ware melted down and cast into pucks. These pucks are stacked into the gun’s magazine, melted with a propane torch and carefully loaded into the gun.

The built-in compressed air tank lacks the oomph to push out the pewter — hence the air compressor, but any lighter liquids or condiments are fair game for rapid-fire exercises. Yes, condiments.

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Fridge Compressor to 2-Stroke Engine: JB Weld for the Win

August 16, 2017 by 24 Comments

We like this one because it has a real Junkyard Wars feel to it: turning a cast-off fridge compressor into a two-stroke internal combustion engine. [Makerj101] is doing this with tooling no more complicated than a hacksaw and a hand drill. And JB Weld — lots and lots of JB Weld.

[Makerj101]’s video series takes us through his entire conversion process. Despite the outward similarity between compressors and engines, there are enough crucial differences to make the conversion challenging. A scheme for controlling intake and exhaust had to be implemented, the crankcase needed to be sealed, and a cylinder head with a spark plug needed to be fabricated. All of these steps would have been trivial in a machine shop with mill and lathe, but [Makerj101] chose the hard way. An old CPU heat sink serves as a cylinder head, copper wire forms a head gasket and spacer to decrease the compression ratio, and the old motor rotor serves as a flywheel. JB Weld is slathered everywhere, and to good effect as the test run in the video below shows.

Think you recognize [Makerj101]? You probably do, since we featured his previous machine shop-less engine build. This guy sure gets his money’s worth out of a tube of JB Weld.

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Making a Coil Gun Without Giant Caps

August 16, 2017 by 24 Comments

Whenever we see a coil gun project on the Internet, it seems to involve a bank of huge capacitors. [miroslavus] took a different approach with his gun–he wanted his project to be built without those monster caps.

It’s powered by quadcopter LiPo batteries, 2x 1400 MaH drone batteries wired up in series and triggering 21SWG copper coils that [miroslavus] created with the help of a custom 3D-printed winding rig he designed. The rigs have ridges to help you lay the coils down neatly, and they also have mounts for photodiodes, ensuring the gun knows when it’s loaded.

When triggered, the Arduino Nano activates a pair of IRF3205 MOSFETS with logic signals stepped up to 20V, shooting lengths of 7mm or 8mm steel rod. The gun isn’t exactly creating plasma discharges with its launches, but it’s a fascinating project nonetheless.

Check out the disposable camera coil gun project and the coil guns for newbies posts we previously ran.

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Alexa In A Bunny Rabbit

August 16, 2017 by 11 Comments

The Raspberry Pi is the perfect candidate for Google’s AIY where you can talk to a cardboard box with some electronics in it. [BuddyCasino] took on the challenge of squeezing an Alexa Client in an ESP32 and to make things interesting, a bunny rabbit was chosen as the host of the virtual assistant.

A few months ago, we did a teardown of the Google AIY Kit where [BuddyCasino] commented that he managed to port the Echo Dot client into and ESP32. Sure enough, the video below shows a demonstration of the build in action. The project uses the MAX98357A which is the same I2S DAC used in the Google AIY Voice Hat. For the microphone, the device is again an I2S component however unlike the Google AIY kit which uses the SPH0645LM4H, [BuddyCasino] opted for the ICS-43434.

Two NeoPixels are employed as visual indicators for various purposes. This project is an excellent example of how simple and cheap modern-day designs have become. We are hoping to see the author add more features to the design and who knows maybe we will see a Google Assistant port on the ESP32 in the future. Check out the original teardown for more inspiration. Continue reading “Alexa In A Bunny Rabbit” →