Another Automatic Air Freshener Use

October 5, 2012 by Jeremy Cook 3 Comments

We’ve seen air fresheners used for many hacks here at hackaday. This one is a bit different as it uses the PIR sensor assembly to turn on LEDs in sequence, rather than reversing a motor. Generally, the motor would be reversed by the fact that this assembly is reversing the voltage on a motor (see [H Bridge] on Wikipedia), but instead it turns on one set of LEDs and then the other.

This works because a diode (the “D” in LED) only allows current to flow one way. The LEDs are reversed with respect to the voltage source, making them come on in sequence. An Arduino or other microprocessor could of course be used to accomplish the same thing (see this [HAD] post about harvesting the PIR sensor only). However, if you had $10 or less to start your hardware hacking career, this is yet another way an air freshener can be hacked up to do your bidding.

Be sure to see the video of this simple hack after the break, used to “LED-ify” a Star Wars AT-ST painting. If you’re interested in using the gears and motor of an air fresher as well, why not check out this post on remotely triggering a camera with the internals from a time-based model? Continue reading “Another Automatic Air Freshener Use” →

Laser-etched LED Zeotrope Looks Like A Circular Monochrome Screen

October 3, 2012 by Mike Szczys 12 Comments

The still image of this animated display really doesn’t do it justice. But you can get an idea of how this really does look like an old monochrome display. It’s actually a zeotrope made from LEDs and etched acrylic. The LEDs blink at a rate that synchronizes with the spinning acrylic to produce an animated image.

You probably already know that a zeotrope uses moving physical models to trick the eye into seeing an animation. In this case the models are etched into a piece of acrylic so that their outline glows when the material is edge-lit. Twelve pie piece shaped panes were designed in Inkscape to look like a scene from the Linux game World War IV. A stepper motor spins the ring which allows for the perfect synchronization seen in the clip after the break.

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Nixie Suduku And On-die LEDs

October 2, 2012 by Brian Benchoff 18 Comments

The best booths at Maker Faire draw you in with something unbelievably cool or ridiculously absurd, and bring out a state-of-the-art technology just as your curiosity for the main feature starts to wane. [John Sarik]’s booth for a class he’s TAing at Columbia – Modern Display Science and Technology – is one of these booths.

The main feature of the booth is a suduku board filled with 81 Nixie tubes. As shown in the video below, you control the cursor (the decimal point of the Nixies) with a pair of pots. After moving the cursor to the desired location, there’s a keypad to change the number at any one of the 81 locations on a suduku puzzle.

[John]’s presentation then continued to what he’s working on up at Columbia: he’s working on a project to put arrays of LEDs onto silicon, just like any other integrated circuit. He demoed a small LED display built in to a DIP-40 package with a glass (or maybe quartz) window. Yes, it’s a really tiny LED matrix display with a pixel pitch probably much smaller than a traditional LCD display.

Video of the suduku machine after the break, as well as a gallery of the LED matrix on a chip. The matrix was very hard to photograph, so if [John] would be so kind as to send a few more pics in, we’ll be happy to put them up. There’s also a proper video from [John]’s YouTube showing off the Nixie Suduku puzzle solving itself with a recursive algorithm.

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Communicating With A Beam Of Light

September 22, 2012 by Brian Benchoff 39 Comments

Last weekend, ARRL, the national association of amateur radio, held a contest called, “10 GHz and up” with the goal of communicating via radio or microwaves over long distances. [KA7OEI] and a few friends decided to capitalize on the “and up” portion of the ’10 GHz and up” contest by setting up a full-duplex voice link over a distance of 95 miles. They used the 478 THz band, also known as red LEDs and laser pointers.

With [Ka7OEI]’s friends [Ron] and [Elaine] perched atop a 5700 foot-high mountain near Park City, Utah, [Gordon], [Gary] and [KA7OEI] trudged up a hill about 10 miles north of Salt Lake City. With the help of a pair of 500,000 candlepower spotlights, the two teams found each other and began pointing increasingly higher power LEDs at each other.

The teams started off with 3 Watt red LEDs before moving up to 30 Watt LEDs and a photodetector at each end. Even though the teams weren’t working with a true line-of-sight – refraction of the atmosphere allowed them to transmit this far – they were able to transmit tone-modulated Morse and even full-duplex voice.

Not bad for a transmission that bends the FCC’s “275 GHz and up” amateur band to its breaking point.

Retroball Or Super Pong Table Grows Up

September 19, 2012 by Jeremy Cook 8 Comments

Retroball is, as its Kickstarter campaign says, “Retro Fun for up to Four Players.” What you might not know, is that it’s ancestor was featured here earlier last year. With a year and a half of development underway, the build looks spectacular, and the people in their promo video look like they’re having lots of fun (obviously).

The whole concept of the game is that it has up to four players that each manipulate a paddle as in the classic Pong game. The obvious difference is that there are four players, and everything is played on a 32 x 32 LED array.

Although it looks like fun in it’s stock form, readers of Hack a Day will most likely start thinking about how they could modify it for their own uses. Everything is open source, and they promise to release the documentation for this project. On the other hand, if you can’t wait, or would rather build something very similar, check out [Brad]’s original Instructable article!

Using An Undocumented Display With An FPGA

September 19, 2012 by Brian Benchoff 11 Comments

When [Mike] ran across a display on Deal Extreme with 8 seven-segment displays, 8 red/green LEDs, and 8 buttons, he knew it would find a good home in a future project. There was only one problem, though: except for an Arduino library, there was absolutely no documentation available for this display. Wanting to use this display with an FPGA board, [Mike] decided against bit-banging a protocol and ported the C++ code into a hardware implementation.

This Deal Extreme display, the TM1638, features enough seven-segment displays, LEDs and buttons to build something really cool, and surprisingly isn’t terribly hard to interface with a microcontroller. The TM1638 library communicates with the outside world via only three pins and a simple serial connection.

After figuring out what commands are sent to make the display turn LEDs on or off, [Mike] wrote a hardware implementation for his Digilent Nexys2 and Digilent Basys2. Now the display operates on an FPGA just like it does with an Arduino, and is a great tool for debugging HDL code for [Mike]’s FPGA.

Helmet Of Many LEDs Built For Burning Man

September 14, 2012 by Mike Szczys 54 Comments

This motorcycle helmet was heavily altered to accept all of the hardware that goes into driving that huge array of LEDs. [Brian Cardellini] built it to wear at burning man. He claims to have been in over his head with the project, but we certainly don’t get that feeling when we see the thing in action. It’s light on build details, but there are plenty of demo shots in the video after the break. The animation and fading action really gets started about a minute and a half into it.

One of the early frames of the video is a shot of the parts order webpage. Since it’s an HD clip we were able to glean a few bits and pieces from that. It includes a MAX7219 LED Display Driver and fifteen 25-packs of Blue LEDs. Now that chip is a great choice, and one of the later shots shows two of them on breakout board driven by an Arduino. The look is very clean since he carved out most of the helmet’s padding to make room for the electronics.

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