Diamonds Are For Data Storage

October 29, 2016 by Al Williams 17 Comments

Most data storage devices we currently use are, at their core, two-dimensional. Sure, a hard drive might have multiple platters, but the data storage takes place on a flat surface. Even an optical drive is effectively a single surface that holds data. At the City College of New York, they are experimenting with storing data in three dimensions using lab-grown diamonds and LASERs.

Usually, diamonds that have few flaws are more valuable. But in this application, the researchers exploit the flaws to store information. Optical memory that uses a volume instead of a surface isn’t exactly new. However, it is difficult to use these techniques in a way that is rewritable.

Diamonds are a crystalline structure of carbon atoms. Sometimes, though, a carbon atom is missing from the structure. That’s a vacancy. Another defect is when a nitrogen atom replaces a carbon atom. Sometimes a vacancy occurs next to a rogue nitrogen atom and that causes an NV (nitrogen vacancy) center.

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Bending The Light

October 28, 2016 by Adam Fabio 17 Comments

Ruled Hyperboloid CC Prof. William McCallum

Everyone knows you can’t visibly bend light over short distances in free air. Or can you? [Jack Pearse] has figured out a way to do it though, or at least make it appear that way. He does it by combining a trick of math and a trick of the eye. The secret is the hyperboloid, a geometric construct described by a quadratic equation. [Jack’s] creation is more specifically a hyperboloid in one sheet. This type of structure allows straight lines to create a an overall curved surface. Hyperboloids have been used by architects and in construction for years, often in tall structures like water towers.

If a bunch of straight steel beams can form a curved shape, lasers should be able to pull off the same effect. By employing persistence of vision, [Jack] was able to create his hyperboloid with only 10 small lasers. The lasers are mounted on the rim of a bicycle wheel and carefully aimed. The wheel is spun up with using an electric bicycle motor. [Jack] kept things safe by building a centrifugal switch. The switch powers up all the lasers in when the tire is spinning. This ensures no one can be hit by a static beam.

Once the wheel is spinning, all you need is a bit of smoke or haze in the room. The spinning lasers combine to form the hyperboloid shape. You can see the project in action in the video after the break.

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Turning Broken Toy Into Laser Target Practice

October 18, 2016 by Elliot Williams 9 Comments

[Mathieu] wrote in with his laser target practice game. It’s not the most amazing hack in the history of hackery, but it’s an excellent example of the type of simple and fun things you can do with just a little bit of microcontrollering.

First off, the gun is a broken toy gun that used to shoot something other than red collimated light beams. The Arduino knockoff inside reacts to a trigger pull and fires the laser for around 200 milliseconds. The gun also has a “gas gauge” that fills up with repeated shots and cools down over time. And therein lies the game — a simple race to ten, where each player only has a fixed number of shots over time.

The targets are simply a light sensor, scorekeeping LED display, and a buzzer that builds tension by beeping at you as the countdown timer ticks down. The bodies are made out of 3D-printed corners that connect some of [Mathieu]’s excess wooden goat-cheese lids.

All the code is up on GitHub so you can make your own with stuff that you’ve got lying around the house. The “gun” can be anything that you can embed a laser in that makes it aimable. Good clean fun!

Cellular Automata Explorer

September 30, 2016 by Gerrit Coetzee 15 Comments

Well all know cellular automata from Conway’s Game of Life which simulates cellular evolution using rules based on the state of all eight adjacent cells. [Gavin] has been having fun playing with elementary cellular automata in his spare time. Unlike Conway’s Game, elementary automata uses just the left and right neighbors of a cell to determine the next cell ahead in the row. Despite this comparative simplicity, some really complex patterns emerge, including a Turing-complete one.

[Gavin] started off doing the calculations by hand for fun. He made some nice worksheets for this. As we can easily imagine, doing the calculations by hand got boring fast. It wasn’t long before his thoughts turned to automating his cellular automata. So, he put together an automatic cellular automator. (We admit, we are having a bit of fun with this.)

This could have been a quick software project but half the fun is seeing the simulations on a purpose-built ecosystem. The files to build the device are hosted on Thingiverse. Like other cellular automata projects, it uses LED matrices to display the data. An Arduino acts as the brain and some really cool retro switches from the world’s most ridiculously organized electronics collection finish the look of the project.

To use, enter the starting condition with the switches at the bottom. The code on the Arduino then computes and displays the pattern on the matrix. Pretty cool and way faster than doing it by hand.

Sending Music Long Distance Using A Laser

September 25, 2016 by Steven Dufresne 48 Comments

This isn’t the first time we’ve seen DIYers sending music over a laser beam but the brothers [Armand] and [Victor] are certainly in contention for sending the music the longest distance, 452 meter/1480 feet from their building, over the tops of a few houses, through a treetop and into a friend’s apartment. The received sound quality is pretty amazing too.

In case you’ve never encountered this before, the light of the laser is modulated with a signal directly from the audio source, making it an analog transmission. The laser is a 250mW diode laser bought from eBay. It’s powered through a 5 volt 7805 voltage regulator fed by a 12V battery. The signal from the sound source enters the circuit through a step-up transformer, isolating it so that no DC from the source enters. The laser’s side of the transformer feeds the base of a transistor. They included a switch so that the current from the regulator can either go through the collector and emitter of the transistor that’s controlled by the sound source, giving a strong modulation, or the current can go directly to the laser while modulation is provided through just the transistor’s base and emitter. The schematic for the circuit is given at the end of their video, which you can see after the break.

They receive the beam in their friend’s apartment using solar cells, which then feed a fairly big amplifier and speakers. From the video you can hear the surprisingly high quality sounds that results. So check it out. It also includes a little Benny Hill humor.

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Real-Life Space Invaders With Drones And Lasers

September 19, 2016 by Elliot Williams 18 Comments

We’ve seen a proliferation of real-life video game builds lately, but this one is a jaw-dropper! [Tomer Daniel] and his crew of twelve hackers, welders, and coders built a Space Invaders game for GeekCon 2016.

[Tomer] et al spent more time on the project than the writeup, so you’re going to have to content yourselves with the video, embedded below, and a raft of photos that they sent us. ([Tomer] wrote in and wanted to thank each of you, and his sponsors, by name, but that would be a couple paragraphs on its own. Condider yourselves all thanked!)
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Hackaday Prize Entry: Characterizing LED And Laser Diodes

September 9, 2016 by Brian Benchoff 15 Comments

Needless to say, we’re fascinated by LEDs, laser diodes, and other blinkies. Although we can get just about any light emitting thing, the data sheets aren’t always accurate or available. For his Hackaday Prize entry, [Ted] is building a device to characterize the efficiency, I/V curve, and optical properties of all the blinkies. It’s a project to make glowy stuff better, and a great entry for the Hackaday Prize.

The inspiration for this project came from two of [Ted]’s projects, one requiring response curves for LEDs, and laser diodes for another. This would give him a graph of optical output vs. current, angular light output distribution, and the lasing threshold for laser diodes. This data isn’t always available in the datasheet, so a homebrew tool is the only option.

The high-level design of this tool is basically a voltmeter and ammeter measuring a glowy diode, producing IV curves and measuring optical output. That takes care of all the measurements except for the purely optical properties of a LED. This is measured by a goniometer, or basically putting the device under test on a carriage attached to a stepper motor and moving it past a fixed optical detector.

If you’re wondering why this device is needed and a simple datasheet is insufficient, check this out. [Ted] measured the efficiency of a Luxeon Z LED, and found the maximum efficiency is right around 10mA. The datasheet for this LED shows a nominal forward current of 500mA, and a maximum of 1000mA. If you just looked at the datasheet, you could easily assume a device powered for years by a coin cell would be impossible. It’s not, and [Ted]’s device gave us this information.