valve

63 Articles

Cams And Pushrods Improve 3D-Printed Compressed Air Engine

April 27, 2018 by 12 Comments

Some folks just can’t leave well enough alone, and that often ends up being a good thing. Such is the case with this 3D-printed compressed air engine, which just keeps getting better.

The design has changed a lot since we first covered [Tom Stanton]’s attempts at reviving the powerplant from the glory days of the Air Hogs line of toys, which he subsequently built a plane around. The engine was simple, with a ball valve that admitted air into the cylinder when a spring mounted to the top of the piston popped it out of the way. That spring has always bothered [Tom], though, compelling him to go back to the drawing board. He wanted to replace the ball valve with one actuated by a cam and pushrod. This would increase the complexity of the engine quite a bit, but with the benefit of eliminating the fail point of the spring. With a few iterations in the design, he was able to relocate the ball valve, add a cam to the crankshaft, and use a pushrod to open the valve. The new design works much better than the previous version, sounding more like a lawnmower than a 3D-printed engine should. Check out the design process and some tests in the video below.

And speaking of lawnmowers that run on compressed air…

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Auto-Tracking Sentry Gun Gives Deer A Super Soaking

January 26, 2018 by 29 Comments

Things rarely go well when humans mix with wildlife. The problems are exacerbated in the suburbs, where bears dine on bird feeders and garbage cans, raccoons take up residence in attics, and coyotes make off with the family cat. And in the suburbs, nuisance wildlife can be an intractable problem because the options for dealing with it are so limited.

Not to be dissuaded in the battle to protect his roses, [dlf.myyta] built this motion-activated sentry gun to apply some watery aversion therapy to marauding deer. Shown in action below against a bipedal co-conspirator, the sentry gun has pretty much what you’d expect under the hood — Raspberry Pi, NoIR camera, a servo for aiming and a solenoid valve to control the water. OpenCV takes care of locating the intruders and swiveling the nozzle to center mass; since the deer are somewhat constrained by a fence, there’s no need to control the nozzle’s elevation. Everything is housed nicely in a plastic ammo can for portability and waterproofing. Any target that stands still for more than three seconds gets a hosing; we assume this is effective, but alas, no snuff films were provided.

We’re not sure if [dlf.myyta]’s code can discern friend from foe, and in this litigious world, hosing the neighbor’s kid could be a catastrophe. Perhaps version 2.0 can include image recognition for target verification.

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The Miracle Of Injection Molding: How Does It Work?

December 17, 2017 by 18 Comments

Pretty much any household item nowadays has an involved, extremely well-thought-out manufacturing method to it, whether it’s a sheet of paper, an electrical outlet, a can of tuna, or even the house itself. Some of the stories of how these objects came to be are compelling, though, as one of the recent videos from [This Old Tony] shows as he takes a deep dive into a $5 ball valve, and uses it to talk about all of the cool things you can do with injection molding.

Injection molding is the process of casting molten plastic into more useful pieces of plastic. In this case it’s a plumbing valve which might seem simple on the surface, but turns out to be much more involved. These ball valves are extremely reliable but have a very small price tag, meaning that a lot of engineering must have gone into their design. What is unearthed in the video is that injection molding allows parts to be cast into the molds of other parts, and the means by which those parts don’t all melt together, and how seals can be created within the part itself. All of this happens with a minimal number of parts and zero interaction from a human, or from any robot that isn’t the injection mold itself.

The video goes into exceptional detail on these valves specifically but also expounds on various techniques in injection molding. Similar to the recognition the seemingly modest aluminum can deserves, the injection molded ball valve deserves a similar amount of respect. While [This Old Tony] usually focuses on metalworking, he often tackles other interesting topics like this and this video is definitely worth checking out.

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Automated Chamber Passes Just The Right Gas

November 15, 2017 by 2 Comments

It sounds like an overly complicated method a supervillain would use to slowly and painfully eliminate enemies — a chamber with variable oxygen concentration. This automated environmental chamber isn’t for torturing suave MI6 agents, though; rather, it enables cancer research more-or-less on the cheap.

Tasked with building something to let his lab simulate the variable oxygen microenvironments found in some kinds of tumors, [RyanM415] first chose a standard lab incubator as a chamber to mix room air with bottled nitrogen. With a requirement to quickly vary the oxygen concentration from the normal 21% down to zero, he found that the large incubator took far too long to equilibrate, and so he switched to a small acrylic box. Equipped with a mixing fan, the smaller chamber quickly adjusts to setpoints, with an oxygen sensor providing feedback and controlling the gas valves via a pair of Arduinos. It’s quite a contraption, with floating ball flowmeters and stepper-actuated variable gas valves, but the results are impressive. If it weren’t for the $2000 oxygen sensor, [RyanM145] would have brought the whole project in for $500, but at least the lab can use the sensor elsewhere.

Modern biology and chemistry labs are target-rich environments for hacked instrumentation. From DIY incubators to cheap electrophoresis rigs, we’ve got you covered.

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Spray Paint Goes DIY Virtual With A Vive Tracker

September 21, 2017 by 11 Comments

Here is a virtual spray painting project with a new and DIY twist to it. [Adam Amaral]’s project is an experiment in using the Vive Tracker, which was released earlier this year. [Adam] demonstrates how to interface some simple hardware and 3D printed parts to the Tracker’s GPIO pins, using it as a custom peripheral that is fully tracked and interactive in the Vive’s VR environment. He details not only the custom spray can controller, but also how to handle the device on the software side in the Unreal engine. The 3D printed “spray can controller” even rattles when shaken!

There’s one more trick. Since the Vive Tracker is wireless and completely self-contained, the completed rattlecan operates independently from the VR headset. This means it’s possible to ditch the goggles and hook up a projector, then use the 3D printed spray can to paint a nearby wall with virtual paint; you can see that part in action in the video embedded below.

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Superconference Interview: Alan Yates

August 26, 2017 by 5 Comments

In 2015, virtual reality was the future, which means we should all have it right now. One of the most technologically impressive VR sets is the HTC Vive, an amazing piece of kit that’s jam-packed with sensors and has some really cool tech going on inside it.

One of the developers of the HTC Vive and the ever-important ‘Lighthouse’ position sensors is [Alan Yates]. He’s of Valve and gave a talk at last year’s Superconference on Why the Lighthouse Can’t Work. Being able to determine the absolute position of the Valve’s headset is hard, but absolutely necessary for VR. Anything else would be an incomplete VR experience at best, and give you nausea at worst.

We sat down with [Alan] after his talk last year, and now that interview is up. You can check that out below.

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Classic IBM TR-2 Flip-Flop Reproduction

July 5, 2017 by 16 Comments

As useful as computers are, most of them have all the design charm of a rubber doorstop. Oh, for the heady early days of computing, when vacuum tubes ruled, hardware was assembled by hand, and engineers always wore a tie.

Looking to recreate an elegant bit of computing hardware from that more civilized age, [updatebjarni] built a reproduction of a 1948 IBM TR-2 flip-flop module — 1,250 of which once formed the memory of the IBM Model 604 Calculating Punch. Admittedly more of a high-speed adding machine than a computer, the 604 is still an important piece of computing history, and [updatebjarni]’s scrap-bin reproduction of the field-replaceable module served as part of a computer history exhibit.

With a single 6J6 double triode tube nestled inside a bent aluminum frame, the goal was to reproduce the appearance of the original TR-2 module, and so the passive components wired up point-to-point style below the tube socket were chosen for their vintage look. That’s not to say the flip-flop won’t function. Although [updatebjarni] hasn’t tested it, he’s built other functional flip-flops from vintage components before, so this one should work too. Only 1,249 left to build and he’ll have enough for a working 604.

If you like this kind of build, you should probably check out some of our Vintage Computer Festival coverage. VCF East in April was a huge success, and VCF West is coming up in August in Mountain View. Hackaday will be well represented there, so stop by.

[via r/geekporn]