World’s Largest Super Soaker is Dangerously Good Clean Fun

Running around while dousing each other with Super Soakers and screaming in delight is de rigueur on suburban lawns on hot summer days, but if you build this giant replica of a Super Soaker that can double as a pressure washer, you might have the upper edge on the neighborhood gang.

You may remember [Mark Rober] from such projects as his bullseye-catching dart board and his previous entry in the awesome uncle of the year awards, the fully automatic snowball gun. We’re not entirely sure that this seven-foot long replica of the original Super Soaker will win him any uncle or neighbor plaudits, given that it the stream it produces is not far off of what a pressure washer can manage and can literally slice a watermelon in half. Fortunately, [Mark] included swappable nozzles to reduce the pressure enough that relatively safe dousing is still on the table. The housing is a pretty accurate plywood and foam replica of the original toy, but the mechanism is beefed up considerably — a pair of nitrogen tanks, some regulators, and a solenoid valve. See the gun in all its window-smashing, kid-soaking glory in the video after the break.

We realize [Mark]’s build is just a fun way to beat the heat, but it gives us a few ideas for more practical uses. Maybe a DIY water-jet cutter that’s not built around a pressure washer?

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Push Button, Receive Beverage!

Here’s a rec-room ready hack: an automatic drink dispenser.

[truebassB]’s dispenser operates around a 555 timer, adjusted by a potentiometer. Push a button and a cup pours in a few seconds, or hold the other button to dispense as much as you want.

The dispenser is made from MDF and particle board glued together, with some LEDs and paper prints to spruce it up. Just don’t forget a small spill sink for any miscalculated pours. You needn’t fret over the internals either, as the parts are easily acquired: a pair of momentary switches, a 12V micro air pump, a brass nozzle, food-safe pvc tube,  a custom 555 timing circuit — otherwise readily available online — a toggle switch, a power supply plug plus adapter and a 12V battery.

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DIY Air Cannon Snags Drones from the Sky

Who hasn’t had the experience of a pesky drone buzzing around that family picnic, or hovering over a suburban backyard where bikini-clad daughters are trying to sunbathe in peace? A shotgun used to suffice for such occasions, but with this compressed-air powered drone catcher, there’s no need to worry about illegally discharging a firearm to secure some privacy.

Before the comment line lights up with outrage, the above scenarios are presented entirely in jest. We do not condone the use of force on a drone, nor do we look favorably on those who use drones in a way that even hints at an invasion of privacy. We can all get along, and even though we hope [Make It Extreme]’s anti-drone gun will never be used in anger, it’s still a neat build that gives us lots of ideas. The rig is essentially four coaxial narrow-bore compressed-air cannons, each launching a slug attached to the corner of a lightweight net. A fairly complex set of linkages sets the spread of the barrels, and a pair of old oxygen tanks serve as reservoirs for the compressed air. A fast-acting dump valve is tripped by an interesting trigger mechanism mounted to a complicated stock and grip; we’d have liked to see more on the fabrication of that bit. The video below shows a test firing that results in a clean takedown of a drone, although we doubt the owner of the quad would characterize it as such.

This build is a bit of a departure from [Make It Extreme]’s usual fare of DIY tools like a shop-built vise or big belt sander, or their unusual vehicles like an off-road hoverboard. But it’s always great to watch a good fabrication video, no matter what the subject.

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Hackaday Prize Entry: Dongle For A Headless Pi

Mass production means that there’s a lot of great hardware out there for dirt cheap. But it also means that the manufacturer isn’t going to spend years working on the firmware to squeeze every last feature out of it. Nope, that’s up to us.

[deqing] took a Bluetooth Low Energy / USB dongle and re-vamped the firmware to turn it into a remote keyboard and mouse, and then wrote a phone app to control it. The result? Plug the USB dongle in, and the computer thinks it sees a keyboard and mouse. Connect the phone via BLE, and you’re typing — even if you don’t have your trusty Model F by your side.

[Deqing] points out that ergonomics and latency will make you hate using this in the long term, but it’s just meant to work until you’ve got SSH up and running on that headless single-board Linux thing. If you’ve ever worked with the USB or BLE specifications, you can appreciate that there’s a bit of work behind the scenes in making everything plug and play, and the web-based interface is admirably slick.

Kudos, [deqing]!

Hydrodipping 101

Style counts, and sometimes all it takes to jazz up the product of a 3D-printer is a 2D printer and a how-to guide on hydrographic printing.

Hydrographic printing, sometimes called hydrodipping, is a process for transferring graphics onto complex-shaped objects in one simple step. A design is printed on a special film which is then floated on the surface of a tank of water. The object to be decorated is carefully dipped into the water right through the film and the design wraps around all the nooks and crannies in one step.

The video tutorial below details the steps to hydrographic printing and outlines how easy the method has become with the availability of water transfer films for inkjet printers. The film is polyvinyl acetate, which is essentially white glue and hence quite soluble in water. The film dissolves and leaves the ink floating on the surface, ready for dipping.

The video lists quite a few tips for optimizing the process for 3D-printed parts and should let you decorate your parts quickly and easily. And once you master the basics, you might want to look at mathematically warping your design to hydrodip complex surfaces.

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Behind the Scenes at a Professional Fireworks Show

Have you ever wondered what goes on behind the scenes at a big fireworks show? Last year [Kenneth] was asked to help manually ignite a fireworks show, and this consisted of him running down a row of shells with a road flare, lighting each one in turn. He apparently did so well that this year worked another show, this one with a more complicated setup.

The show [Kenneth] helped run consisted of 950 three-inch shells, wired in series into small groups, plus another 150 in 25-shell clusters used for the finale. The fireworks were organized in racks consisting of five three-inch diameter tubes of HDPE secured together by 2x4s. Each tube held a shell, and each shell came pre-wired with both a match fuse and electrically-triggered squib. Each squib or series of squibs connects to 45-channel breakouts, which connect to a control board.

Even after the show was completed, [Kenneth] had work to do, walking around and looking in each tube to see if there are any unfired shells. The dual wiring is so the shell can be fired with a flare if the squib is a dud. In this show they found six shells, and [Kenneth] was tasked with setting off those last shells with a road flare—otherwise they’d have to use a licensed and placarded vehicle just to transport a few shells.

For more fireworks goodness checkout this beautiful Arduino fireworks controller and this network-controlled fireworks launcher.

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A 3D Scanner that Archimedes Could Get Behind

3D-scanning seems like a straightforward process — put the subject inside a motion control gantry, bounce light off the surface, measure the reflections, and do some math to reconstruct the shape in three dimensions. But traditional 3D-scanning isn’t good for subjects with complex topologies and lots of nooks and crannies that light can’t get to. Which is why volumetric 3D-scanning could become an important tool someday.

As the name implies, volumetric scanning relies on measuring the change in volume of a medium as an object is moved through it. In the case of [Kfir Aberman] and [Oren Katzir]’s “dip scanning” method, the medium is a tank of water whose level is measured to a high precision with a float sensor. The object to be scanned is dipped slowly into the water by a robot as data is gathered. The robot removes the object, changes the orientation, and dips again. Dipping is repeated until enough data has been collected to run through a transformation algorithm that can reconstruct the shape of the object. Anywhere the water can reach can be scanned, and the video below shows how good the results can be with enough data. Full details are available in the PDF of their paper.

While optical 3D-scanning with the standard turntable and laser configuration will probably be around for a while, dip scanning seems like a powerful method for getting topological data using really simple equipment.

Thanks to [bmsleight] for the tip.