RC Plane Built Using Pieces Of An RC Car

This hack’s old as dirt to be sure, but new to us and a great accomplishment. The plane above, which is meant to fly without an operator, has been given RC control thanks to parts from that little car. The transmitter and receiver pair are the obvious transplant, but how do you add steering to a $7 plane that wasn’t manufactured to have that feature? The tail was cut and reconnected with mylar hinges to turn it into a rudder. A rare earth magnet and a coil are also thrown into the mix to provide movement. Basically this is a simple solenoid where the coil pushes against the magnet when energized, actuating the rudder. This in combination with an upgraded motor allows for both speed control and yaw. It doesn’t look like you can control roll and pitch but what more can you really expect?

This would be a nice first step on that path to building an epic flying camera rig.

[Thanks Rob]

Lego Machine Predicts Future Eclipses

Hidden behind the white face plates of this machine are racks of gears that make up a replica of one of the oldest known mechanical computers. This is a working model of the Antikythera mechanism made from Lego pieces. In the video, which you absolutely can’t miss after the break, The machine is disassembled into its various components. Each mechanical unit takes advantage of gear ratio combinations to perform numerous levels of mathematical functions in order to display the date and time that future celestial events will occur.

The background information on the original device reads like the script for a sequel to The Goonies. Believed to date back to 100-150 BC, the stone bronze mechanism was recovered from a shipwreck around the turn of the twentieth century. The use of x-ray analysis helped to unlock the functions and confirm the theories of its operation.

Part of what makes this so interesting is the historical connection. But the production quality of the video (which to be fair, seems to be an advertisement) really brings home how complicated this process is. Now it’s time for us to watch the video a few more times, sketching out the gearing to see that this works as they say it does.

Want more of the Antikythera mechanism? Check out the model built by [Tatyana van Vark].

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Nerf Gun Converted To CO2 Powered Semi-automatic

[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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Radar Gun Teardown

[Jeri Ellsworth] is at it again, this time she takes apart a hot wheels speed gun and in the process she does a good job of  explaining how radar can be used to measure speed.  She also demonstrates a way to determine if an object is approaching or receding from the radar gun.

The Doppler shift is one way to remotely measure the speed of an object. It works by measuring the change in frequency of a wave after it strikes an object. Rather than measuring the Doppler shift of the returning wave most radar guns use the phase shift. The reason is that the frequency shift of a relativly slow object (60mph), to a relitivly high frequency signal(10GHz) is small (about 0.893Hz), where the phase shift varies based on the distance of the object.  This is all just a stepping stone in her quest to build a crude TSA body scanner.

Epic Wooden Marble Run For Kids’ Room

Some parents buy kinetic sculptures for their kids at art or craft fairs. Not [Steve Moseley], he turned his kids’ hovel into a sculpture by wrapping a marble run around the entire room. It’s big enough, with so many features that finding a banner image was a bit tough. After the break we’ve embedded a video where you’ll see a wagon wheel lifter, plenty of gravity-fed curves, loops, inclines, rockers, a stair-step lifter, and… well you get the idea.

Considering the scope of the project it was remarkably inexpensive; about $70 in wood, $40 for the glass marbles, and around $60 for everything else. We’re glad he shared his building methods with such verbosity. You’ll need a well-stocked shop. Fine work like this requires tools common for woodworkers, but we’d bet the band saw and oscillating spindle sander were a godsend.

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Playing Hacker With A Toy Vault

[Thomas Cannon] created his own hacking game by adding some circuitry to this toy vault. The original toy uses the keypad to control a solenoid keeping the door shut. He kept the mechanical setup, but replaced the original circuit board with his own ATmega328 based internals. He also added a USB port to the front. The gist of the game is that you plug-in through USB to gain access to the vault’s terminal software. If you can make your way through the various levels of admin access the loot inside will be yours.

Girltech. Sugar Cubes. Monocrome LCD

We’ve seen these little toys called “sugar cubes” by GirlTech around for a while now. They are a toy block, with an LCD on the front and they respond to movement, button presses and they interact with each other if you stack them up. We’re just as curious as anyone else about their internals, but maybe not quite curious enough to rush out and buy one. Luckily, we don’t have to as [Joby] has done it for us and documented what he found. While it may be lacking in extreme detail, at least our curiosity is somewhat satiated.
We can see that it has a 16×16 LCD, an unknown chip hidden under an epoxy blob as usual. To determine what character is shown, you can bridge one of 4 spots on the PCB, though he has only managed to switch to a little ninja and a question mark. Does anyone have any brilliant ideas on a project for these?