German Engineering Produces An Overcomplicated Scarecrow

December 21, 2010 by Mike Szczys 16 Comments

This electronic scarecrow keeps the birds away and makes your neighbors hate you at the same time. That’s because its way too loud, even if the next house is far away. The conrad.de folks that brought us the climbing bike storage device are at it again, putting together car audio and strings of lights as part of the bird-shoo-ing technology. In the video after the break you’ll see that they’re using a PIR motion sensor to switch power to an automotive amp and head unit. The speakers, strings of lights, and spinning doo-dads are all hidden under a black cape. When an unsuspecting bird tries to feast on the crops, the scarecrow unfolds its arm Dracula-style and raises a ruckus. We don’t expect to see this at a local farm, but maybe for next Halloween?

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Home Brew Coffee Machine

December 8, 2010 by Joseph Thibodeau 23 Comments

There are already a lot of different ways to brew up a decent coffee at home, from the humble saucepan to the elegant vacuum flask. In an office environment the choice of coffee-making technique can have a major impact on workplace harmony—how can people be expected to work happily when the kitchen is filthy with grounds and the coffee is always stale? “Someone have mercy,” [Christian Finger] lamented, “and boil a pot of fresh.”

In the end he took extreme measures, building a machine that grinds whole beans, measures out a dose, brews a cup and self-cleans. He used all sorts of odds and ends to put the thing together, detailed in his long and hilarious build log (english translation—and check out the dude’s sweet ride). Refer to his shockwave animation for a summary of the intended operation.

The end result is an extremely impressive Goldbergian contraption—download the video from the build log. It is pretty noisy and probably energy- and water-hungry, but that wouldn’t stop us from using it every day, if given the chance. Hell, this here could form a major part of your next breakfast machine.

We’re sure that there is further potential in this, because to get the really freshest possible cup of coffee you’d want to roast the coffee beans just before grinding them. Then you’d be well on your way towards something else entirely: a delicious breakfast machine.

Copper-clad Enclosures

December 8, 2010 by Mike Szczys 29 Comments

Building a great looking box for your projects can be a challenge. [Ken] boils down his process of building enclosures out of copper clad (PDF) circuit board material into an illustrated guide in case you want to try this for yourself. Why would you want to use PC board? The fiberglass substrate makes for a strong and lightweight material. Also, [Ken] is a ham radio operator and the copper coating acts as an electrical shield for delicate components inside.

As you can see above he uses solder to tack the pieces together. There’s some important considerations that go along with this method. First, he cuts the pieces just a bit oversized and then sands them flat and square before assembly. Next, he uses some 20 gauge wire as a shim between a ninety-degree joint and a right angle jig. This shim compensates for the shrinking that occurs as the solder cools, making sure the joint gets pulled to a right angle. He even solders nuts in place so that screws can be used to attach the case cover to the chassis.

Yesterday we saw toner transfer used to make labels on an ABS case. If you make your enclosure out of copper clad, using toner transfer for panel labels will be a snap!

Tuesday Two-Fer: Battery Cases And ABS Lettering

December 7, 2010 by Mike Szczys 13 Comments

These are both interesting, unrelated, and can’t quite stand on their own so we threw them into one post.

On the left you see the product of using toner transfer on ABS plastic. [Bogdan] tried this out as a way to make front panels for his enclosures. It really shouldn’t work very well because ABS has a lower melting point than toner does. But it seems that it takes a while for the ABS to heat up. If you’re quick, ironing for about 10 seconds, you can get the toner to stick to the plastic and then soak the paper off, leaving your printed design looking nice and clean.

To the right you see a printed battery case. [Nikolaus Gradwohl] ran across the same problem we’ve face many times: how to attach batteries to your projects? We’ve duct-taped them together, used the blister packs they’re sold in, Dremeled them out of thrift-store toys and just about every other thing you can imagine. He decided to make them easy to manufacture with a 3D-printer. This is accomplished with an OpenSCAD file he wrote. Plug in the size and number of batteries and a printable package will be automatically generated.

Nerf Gun Converted To CO2 Powered Semi-automatic

December 3, 2010 by Mike Szczys 33 Comments

[Philysteak527] modified a Nerf rifle, making it semi-automatic thanks to the powers of compressed air. This is not a simple change to make, and rests on his ability to design and manufacture a bolt-action that fits in the gun, works with the Nerf ammo, and uses a CO2 canister and solenoid valve for the firing action. Knowing that, it’s not surprising to find that he’s an engineering student at Stony Brook University. He started with some POM, or polyoxymethylene plastic sold under the brand name Delrin, and used a CNC lathe to machine the parts for the bolt. Add in some brass fittings, a solenoid, tubing, and the electronics and you’re in business.

We’ve embedded the test footage after the break. Looks like the new internals allow a rather fast firing rate (maybe 2-3 shots per second?) and achieve a distance between seventy and one hundred feet.

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Water-blob Launcher

December 3, 2010 by Mike Szczys 39 Comments

This rifle-shaped water cannon looks great and packs a big punch. We guess you could say that it’s a water balloon launcher, but the balloons are torn off and drop like the wad from a shotgun shell when fired. So we think this launches water blobs, or orbs, or something along those lines.

[Wolf] built it using PVC and some brass fittings that allow for the injection of compressed air. There’s a slick valve system that he developed which we don’t get a great look at in the build pictures. Fortunately, there’s an animated GIF that shows the various stages. Using his valve there’s no need for any electrical system like a lot of other pneumatic launcher systems use.

Just like the water-filled ping-pong gun, you’ve got to be careful with this thing. As you can see in the clip after the break there’s lethal force behind these projectiles. Especially when [Wolf] swaps out the water balloons for big steel darts.

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Hopefully Detect Trolls Before They Devour You

November 25, 2010 by Joseph Thibodeau 24 Comments

In the cold and mysterious wilderness of Norway, it pays to be ready for anything–especially heavy-walking trolls. The team at [nullohm] decided to prepare thoroughly for their trek into the woods to witness the Leonids meteor shower by putting together an Arduino-based “troll detector”.

The device is based on the superstition of hammering a steel spike into a tree to keep trolls away from camp. This goes one step further by including an accelerometer and LED indicators so that you can tell exactly what type of troll is just about to feast upon your tender human flesh.

When the detector is installed into a nearby tree, it takes an average seismic measurement and then looks for telltale footfalls. Even if you’re not concerned with perpetuating superstitions, you might find a use for the source code for simple seismic activity monitoring at home to supplement your miniature seismic reflector.