I need someone to explain this to me.

3D Printed AR-15 Lower Works

Ar15.com user [HaveBlue] has been working for some time on a 3D printed lower receiver, and now reports that the parts are fully working. Using a Stratasys 3D printer from the 90′s [HaveBlue] managed to spin out a modified version of an already available model from cncguns.com. He strengthened the holes for the takedown lugs, which hold the upper and lower halves of the rifle together. Strengthened the bolt hold lugs, which when the magazine is empty lifts a lever assembly that catches the bolt as it springs back to push another round into the chamber. and added an integral trigger guard AKA the bar that surrounds the trigger.

Legally this print is a veritable gauntlet of state and federal regulations. At least in the US. The lower receiver is the part of the rifle that holds the spring and pins that operate the rifle’s trigger safety and hammer assembly, hold the magazine in place,  and mount the buttstock/return spring tube. The other key point about the lower receiver is that it contains the primary traceable identification markings, the serial number. All of the parts that are contained within the lower receiver can be ordered online (this varies state to state). In fact, every single other part of the rifle can be bought and sold freely. The only component of the rifle that can not be ordered online, and requires a background check at a gun store, is the body of the lower receiver (we have to keep saying that this varies state to state). Typically laws allow though for the manufacture of this part without a serial number so long as it is never sold to another individual (again, state laws vary widely).

There is some more info on the build at [HaveBlue]‘s website here and here, but it is currently down.  This sort of steps up 3D printing past the nerf gun stage, but we have seen shot gun and pistol hacks.

Create a laminar flow jet without pesky fiber optics.

[ApexLogic] had some PMMA core acrylic rod rod left over from a project and decided to use it as the lighting element in a laminar flow water jet.

The typical water jet consists of a bunch of sponges and drinking straws sandwiched together to slow a rough water stream and then a finely cut nozzle to provide a smooth ripple-free strand of clear water. If light is applied to this stream of water it tends to act similarly to fiber optics. [ApexLogic], however, uses a combination of shaved PVC filings, Brillo, and what appears to be most of the plumbing aisle of a local hardware store to get the same laminar flow. To top it off the polished acrylic rod is much less fragile than its glass-fiber counterpart and can have a high power light glued to the end for a nice water tight seal.

The system currently runs off of garden hose pressure, and would probably need some kind of a boost before it went into that front yard mega fountain that [Caleb] is still waiting for somebody to make.  If you still need some clarity on laminar water jets check out these videos on a few

Anti-Sanecraft ARTillery Cannon is farm boy engineering at its finest

The term “just enough knowledge to be dangerous” comes immediately to mind with this one. The official description is “a large scale pan and tilt propane Flame Effect” but that hardly does this thing justice. The Anti-Sanecraft ARTillery Cannon is a three-barrel fire cannon that can move around like its namesake and launch massive propane bursts from two 1″ diameter barrels. The third barrel is somewhat special, it is constructed of stronger steel and can be pre-fed with oxygen to create one massive intense propane-O2 mixed fire burst.

The trick about the whole thing is that when oxygen and propane are mixed it is a highly volatile and dangerous thing, in a closed space they classify as an explosive. Instead oxygen is filled directly into the open ended barrel separately and is allowed to sit until propane fires it out. This mixes the two fuels in the open air where it is safer and far away from any bystanders. We would not suggest you try this at all ever, as the effect was so loud during the Transformus festival that neighbors, miles away from the large festival ground, were complaining  about rattling windows. This is the kind of place where several thousand watt sound systems are pushed near the red with no issue, just to give a bit of a comparison.

We can’t seem to find a video of this thing in action either [Beyond Joy] just posted a video of this crazy contraption in action (without the O2 effect), check it out after the jump! Don’t forget to check the facebook photo album for all the NPT pipe fitting action, (warning some images of the phallic controls are very mildly NSFW).

Photo Credit: [Bert Reed Photography]

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Incredible home made low cost CO2 Laser

[LokisMischief] wrote in to the tip line to let us know about this incredible home made CO2 laser. This thing is a complete DIY beauty, from the PVC cooling jacket to the toolbox based controller.  The whole thing is essentially built from DIY parts,  hand blown glass for the laser tube, plumbing store mirror mounts,  a PVC cooling jacket with a caulked glass viewing window, and a neon sign transformer with a variac to control output. Even the optics are completely DIY, a hand drilled gold mirror and a NaCL window made from a polished chunk of  icecream salt! [ThunderSqueak] says the control box only cost 60 bucks, and the rest of the parts don’t look too terribly expensive.

We could only find one video of the setup in the variac section of the site, and it was just a test the amp meter in the controller (no lasing anything at all).  [ThunderSqueak] does make a note on the to do list about doing a good laser-y demonstration video, which we are looking forward to.

If you want more DIY CO2 laser action check out this other one or some plans for one.

One Enormous Breadboard

[Franklyn] wrote in to tell us about the The Hack Factory Big Board project. The Twin Cities Maker group, a Minneapolis/St Paul based hackspace, set out to provide an education tool to help students make the leap from schematic diagrams to bread board connections.   Naturally their conclusion was to create a humungous 10x scale bread board.  The board features scaled up yet fully functional capacitors, resistors, a dip switch, and the jumbo-est LEDs we’ve seen in a long while.

Like its 0.1″ pitch counterpart, passive components can be thrown in 1″ pitch breadboard to create a myriad of analog circuits. The Twin Cities folks even tossed together an optical theremin using a scaled up photoresistor.  Beyond analog circuits the board can also demonstrate various ICs using either a custom breakout board featuring an 8-pin DIP socket or a vacuum formed Atmega 328 which boasts an internal Arduino Uno. The cool thing about the giant 28-pin DIP is that it does not necessarily function as a microcontroller.  Instead the UNO will be loaded with chip emulation programs geared towards the lesson at hand,  jumpers  select programs to teach debouncing, logic, flip-flops, and a whole slew of other basic concepts.

We are a bit concerned that the next logical step is a gigantic soldering iron,  but at least we finally have something to interface to the huge liquid crystal display.  If you still want more giant circuit stuff check out this 555 footstool.

Check out a quick intro video after the jump!

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I build stuff too! Fire Cannon Edition

After hanging around festivals and burners for a bit I decided that it was finally time to show my stuff and actually build one of these crazy fire cannons everyone is always talking about.  The easiest way to go about this would have been to just follow plans from any given website: replace the valve from an empty grill tank with a 4 way fitting, add an electric solenoid, barrel, low pressure regulator (for the pilot), and then pipe in a regulated propane source. Easy.  The problem My problem with this stock fire cannon design is that it looks like every other fire cannon out there, you have your off the shelf propane bottle and a long thin copper barrel poking up from it, the fire is nice but the cannon is not very fun to look at. Also you can only fit a given size valve, and that does not allow for very much fuel to be released at once. This limits the size of the plume of fire, and where is the fun in that.  The central idea is to add lots of little bottles instead of one big one; I stumbled on a nice pretty anodized aluminum water manifold and the idea grew out from there.

Now, keep in mind I did not just set out to build this crazy thing out of nowhere and slap everything together without laying out some plans. I have been working with the folks over at Frank’s Kitchens for some time, and have been able to pick up a lot of safety practices and general safe handling procedure to keep myself from burning down the entire county. If you want to set out to make a flame effect that is great, but just read up on safety first and try to check out a fire cannon in person… That’s what I did and I still have most of my eyebrows as a result (no arm hair though).

Enough freaking text. Check out the video below for a tour!

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ATiny powered Kinect fire cannons for dance Fx

[Paul] is at it again with some kinect controlled fire poofers. You may remember [Paul's] previous shenanigans with the gigantic hand made hydraulic flame-sailed pirate ship.  This time he is building a small flame poofer (possibly a series of poofers) for SOAK, a regional (unaffiliated) Burning Man style festival in Oregon.

Any one who remembers the build will recognize the brains of the new cannons, they are just the pirate ship’s custom ATiny board unceremoniously torn from their previous home and recycled for the new controller. This time though they have Kinect! The build seems to function much like the evil genius simulator by simply using a height threshold to activate each cannon, but [Paul] has plans for the new system. This hardware test uses the closed source OpenNI but will meet its full potential when it is reborn in SkelTrack, which was just released a few weeks ago. The cannons are going to go around a small single person dance floor, presumably with the Kinect nearby.

Check out the brief test video after the jump.

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