How A Quarter Shrinker Works

September 28, 2012 by Mike Szczys 43 Comments

This machine is capable of shrinking coins. What you’re looking at is actually a 3D model of the Geek Groups impulse generator, which is called Project Stomper. The model is used to explain how induction shrinks a quarter to the size of a dime.

The grey chamber to the left is a reinforced containment device. It’s a safety feature to keep people in the same room as the Stomper safe from flying particles which may result from the forces this thing can put out. You see, it uses a mountain of magnetic energy to compress the edges of a coin in on itself.

As the video after the break illustrates, the main part of the machine on the right starts off by boosting mains voltage using a microwave oven transformer. This gets the AC to 2000V, which is then rectified and boosted further to get to 6000V DC. This charges three huge parallel capacitors which are then able to source 100,000A at 6 kV. When it comes time to fire, the charge is dumped into a coil which has the coin at its center. The result is the crushing magnetic field we mentioned earlier.

This isn’t a new concept, we featured a different coin crusher build in the early years of Hackaday’s existence.

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Never Pay More Than $10 For A Projector Mount

September 28, 2012 by Mike Szczys 8 Comments

[Lou] needed to mount his projector to finish up his home theater. But he was rather put off by the cost of commercial solutions. He ended up building his own projector mount for about ten bucks. The technique reuses some scrap metal and sources connectors from the hardware store. If your projector will be mounted flat to the ceiling we think this will work just as well for you as it did for him.

To the left we get a good look at the two parts which make up the mounting bracket. [Lou] is reusing a metal warning sign. One large piece is attached to the back portion of the projector and hangs over the end about a half-inch. On the front there is a tab with a slot in it made out the same sign. The slot accepts the head of a three-inch drywall screw. There are two holes in the rear piece which also receive screws. Once the projector is in place the screws can be adjusted to achieve the proper projection angle. [Lou] does a full walk through of the project in the video after the break.

This goes perfectly with the $50 projection screen that he built.

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Hand Cranked Electric Toy Has No Batteries Or Power Supply

September 28, 2012 by Mike Szczys 20 Comments

We think this hand cranked robot design is nothing short of absolute brilliance. The toy is remote-controlled through a short section of wire. It can drive forward and turn, but not at the same time. Still that’s impressive considering it uses no battery or power supply and, of the two servo motors, only one is actually in the robot itself.

The second servo, which is visible to the right, acts as a dynamo. When you crank it electricity is generated. The inputs of that servo are connected to the inputs of the one in the robot to power it. If you crank in one direction the colorful toy will drive forward. But there is a one-way catch on one of the side wheels so when the servo is cranked backward the little guy actually executes a reverse turn. The magic of building a project like this is perfect for a weekend activity with the kids. Don’t miss the demo embedded after the jump.

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Wearable Raspberry Pi Turns You Into The Borg

September 28, 2012 by Brian Benchoff 42 Comments

The Hoboken hackerspace, MakerBar, recently hosted a very special guest – [Rob Bishop] from the Raspberry Pi Foundation. Wanting to impress [Rob], [Zach] and a few others from MakerBar put together a wearable computer based on the Raspberry Pi in just a few hours.

Putting a Raspi, small Bluetooth keyboard and mouse combo, and a USB charger equipped with lithium-ion battery wasn’t that hard. The tricky part was finding a wearable display. Luckily, [Zach] had a pair of MyVu Crystal video glasses lying around and after a tricky bit of dissassembly, the folks at MakerBar had a completely wearable computer.

Apart from the RCA cable connecting the Raspi to the glasses, the project is completely wireless; with a small webcam also mounted to the display, the Pi in the Face could easily be a platform for figuring out what to do with Google Glass.

[Zach] said the entire setup could be reconstructed for about $100, a fair price for being turned in to [Locutus] of Borg

Making Logic Gates Out Of Crabs

September 28, 2012 by Brian Benchoff 37 Comments

Building logic gates out of silicon is old hat, as is building them from discrete transistors, 555 chips, LEGO, and even gears. [Yukio-Pegio Gunji] and [Yuta Nishiyama] from Kobe University, along with [Andrew Adamatzky] from the aptly named Unconventional Computing Centre at the University of the West of England decided they needed a new way to build logic gates using crabs (PDF warning). Yes, the team successfully built functional logic gates using Mictyris guinotae, a species of soldier crab native to the South Seas.

The colonies of soldier crabs that inhabit the lagoons of Pacific atolls display a unique swarming behavior in their native habitat. When in a swarm of hundreds of individuals, the front of the swarm is driven by random turbulence in the group, while the back end of the swarm simply follows the leaders. Somehow, this is a successful evolutionary strategy, but it can also be exploited to build logic gates using only crabs.

The team constructed a Y-shaped maze for a pair of crabs to act as an OR gate. When two soldier crabs are placed at the top of the ‘Y’, they move forward until they meet and exit the maze through the output. This idea can be expanded to a slightly more complex AND gate, functionally identical to the electron-powered AND gate in a 7408 logic chip.

While the team has only made OR and AND gates – nothing functionally complete yet – there’s no reason to believe this crab-based system of computation couldn’t be expanded to a (very) basic calculator.

Massively Parallel Computer Costs $99

September 28, 2012 by Brian Benchoff 89 Comments

Even though dual, quad, and octo-core CPUs have been around for a while, it’s a far cry from truly massive parallel computing platforms. The chip manufacturer Adapteva is looking to put dozens of CPUs in a small package with their Parallella project. As a bonus, they’re looking for funding on Kickstarter, and plan to open source their 16 and 64-core CPUs after funding is complete.

The Parallella computer is based on the ARM architecture, and will be able to run Ubuntu with 1 Gig of RAM, a dual-core ARM A9 CPU, Ethernet, USB, and HDMI output. What makes the Parallella special is it’s Epiphany Multicore Accelerator – a coprocessor containing up to 64 parallel cores.

Adapteva is turning to Kickstarter for their Parallella computer to get the funding to take their Epiphany multicore daughterboard and shrink it down into a single chip. Once that’s complete, Adapteva will start shipping an ARM-powered Linux supercomputer that’s about the size of a credit card, or a Raspberry Pi under the new system of dev board measurements.

With any luck, the Parallella multicore computer will be available for $99, much less than a comparable x86 multicore computer. It’ll certainly be interesting to see what the Parallella can do in the future.

Doorbell To Internet Bridge Also Useful For Other Home Automation

September 28, 2012 by Mike Szczys 5 Comments

This wireless doorbell hack can send a text message when someone rings. Adding the hardware to the chime unit turned out to be quite simple. It shows potential for a slew of other applications.

[Martin] started the project with a breakout board he had designed for an RFM12B wireless transceiver board. This board is popular because of its low-cost, small size, and ease of operation. [Martin’s] breakout is barely larger than the RFM module itself, and merely adds an ATtiny84 to the mix. In the case of this doorbell project he uses a pin interrupt to detect when the doorbell’s LED is illuminated. This wakes the chip from sleep and sends a message back to the receiver that something has happened.

The receiver can do anything it wants with that data. In this case it uses an email-to-SMS service to send [Martin] a text message. But the home automation applications are vast for this simple hardware. We have a water heater that is not near a floor drain so we use a simple leak detector to sound an alarm if there is ever a problem (the water heater sits in a shallow tray). That works if we’re home at the time. Using [Martin’s] solution could extend that alarm’s reach worldwide.

[via Hacked Gadgets]