Color Changing EL Wire

July 13, 2011 by Brian Benchoff 34 Comments

All EL wire drivers use a resonator circuit to supply power to the EL wire. It’s an efficient system, but [Paul] noticed that there was some color change when powering different lengths of wire off of the same driver. He realized that this is because of the changing frequency of the resonator circuit, so the only reasonable thing for [Paul] to do was to build a color fading EL wire driver.

The circuit used to drive the wire is very simple. [Paul] used a Teensy board to switch two transistors and produce AC current. This is sent through a step-up transformer which powers the EL wire. It was necessary to use aqua or ‘Tron blue’ EL wire for this build because of the clear wire jacket. Many colors of EL wire have a fluorescent jacket – much like a fluorescent light bulb – that changes the color produced inside the wire to something different. [Paul] says the color change is subtle, but unique.

Of course the build is nothing without a video of the color changing EL wire. Check it out after the break.

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DIY Wiper Speed Control And Collision Avoidance

July 13, 2011 by Mike Nathan 24 Comments

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On many new cars, automatic wiper speed control can be had as an upgrade, though most cars do not offer front-end collision prevention at all. [Rishi Hora] and [Diwakar Labh], students at the Guru Tegh Bahadur Institute of Technology in New Delhi, developed their own version of these features, (PDF warning, skip to page 20) which they entered into last year’s Texas Instruments Analog Design Contest. Under the guidance of professors [Gurmeet Singh] and [Pawan Kumar], the pair built the systems using easily obtainable parts, including of course, an MSP430 microcontroller from TI.

The collision prevention system uses a laser emitter and an optical detector to estimate the distance between your car and the vehicle in front of you, sounding an alarm if you are getting too close. In a somewhat similar fashion, the wiper speed control system uses an IR emitter and detector pair to estimate the amount of water built up on the windshield, triggering the wipers when necessary.

While not groundbreaking, the systems would be quite handy during monsoon season in India, and seem easy enough to install in an older vehicle. The only thing we’re not so sure about is pointing lasers at cars in traffic, but there are quite a few available alternatives that can be used to measure distance.

Continue reading to see a video walkthrough and demonstration of both systems.

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Building A Solar Power Heliostat

July 13, 2011 by Brian Benchoff 16 Comments

[Frits] has been working on an solar panel heliostat (in Dutch, check out the translated page here).

The heliostat uses a small PICAXE to control the motor, along with an DS1307 real-time clock to make sure the motors start at dawn. Instead of using optical encoders or magnetic sensors, the angle of the heliostat is measure with a pot attached to the drive shaft. [Frits] did a lot of data collection to figure out that this method is accurate to about 1 degree – just fine for something that doesn’t need to be exact.

According to [Frits] this heliostat will put out 12 to 50 percent more electricity than a fixed panel. Although the build does seem a little bulky, putting it on a house with a roof pitch of 23.5° would greatly reduce the horizontal profile.

A video of a solar panel rotating at 15 degrees/hour isn’t that interesting, so [Frits] posted a clip of 6 mirrors slewing around fairly fast to demonstrate his system. Check it out after the break.

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Automotive Battery Voltage Monitor

July 13, 2011 by Mike Nathan 32 Comments

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[Rajendra’s] car had just about all the bells, whistles, and gauges he could dream of, but he thought it was missing one important item. In an age where cars are heavily reliant on intricate electrical systems, he felt that he should have some way of monitoring the car’s battery and charging system.

To keep tabs on his car’s electrical system, he built a simple device that allows him to monitor the battery’s instantaneous voltage when the car is powered off, as well as the charging voltage across the battery when the car is running. A PIC16F1827 runs the show, using a simple voltage divider network to step the input voltage down to an acceptable level for use with the PIC’s A/D conversion channel. The resultant measurements are output to a four digit 7 segment display, mounted on the front of the device.

He says that the voltage monitor works quite well, and we’re sure he feels a lot better about the health of his car’s charging system. For anyone interested in keeping closer tabs on their car, he has a circuit diagram as well as code available on his site.

Faux LED Scroller Using Phosphorescence

July 13, 2011 by Mike Nathan 38 Comments

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Hackaday reader [BGR] wrote in to share a video he put together showing off a cool “poor man’s LED scroller” that he built. Rather than build a huge array of LEDs, spending tons of time time wiring and programming, he decided to use only a handful of LEDs on a moving display instead.

The scroller is built upon a PIC16F887 microcontroller which resides on an EasyPIC6 dev board he borrowed for the project. The PIC controls a strip of eight bright white LEDs, which are used to write text on a long strip of phosphorescent paper that can be found at many printing supply outfits. The paper’s dispensing mechanism was cobbled together with parts from several sources, including a laser printer and VCR.

When he wants to display a message, he inputs text into a flash application he wrote. The app sends the LED byte values to his scroller via a separate serial proxy that talks to the pic over his computer’s COM port.

The effect is pretty slick, looking similar to a slow-moving diffused LED scroller. The messages disappear after about 5 minutes in a pitch black room, which is perfect, since he originally intended to use the device for displaying Twitter updates. He is already considering a second revision of the project, which he wants to mount on the wall – sounds great to us!

Be sure to swing by YouTube to see the video, or continue reading to watch it here.

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Xbox 360 DVD Changer Is The Ultimate In Gaming Laziness

July 12, 2011 by Mike Nathan 33 Comments

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Let’s face it – gamers have a reputation for being pretty lazy. In the most recent episode of his web series, [Ben Heck] takes on the stereotypical gamer role and cranks the laziness factor to 11, lamenting the fact that he needs to get up off the couch to swap discs in his Xbox 360 console. Never allowing laziness get in the way of his hacking, he springs into action, hauling off to his shop in order to construct an Xbox DVD changer system.

He grabbed a pair of CD changers and popped them open to see how they operated. After choosing the best candidate based on its CD loading method, he got to work disassembling the changer. The old CD player and its guts were removed, which he replaced with DVD drive components ripped from his Xbox. Quite a bit of trimming and tweaking was required to swap out the components, but it seems that [Ben] got things working just fine.

With the mechanical portion of the project out of the way, he dug into the electronics. The CD changer had no way of knowing how to interface with the Xbox and vice versa, so [Ben] had to devise a way for the two devices to communicate. He used an Arduino Uno to control the systems, triggering the CD carousel only when the Xbox thought it had its drive slot opened.

While the system looks a bit unpolished, and the controller quite bulky, we love this thing! No matter if you are lazy or not, jamming these two devices together is exactly what hacking is all about.

Shoulder Surfing With OpenCV

July 12, 2011 by Mike Nathan 14 Comments

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While it seems that many people are wise to shoulder surfing, keeping a lookout for anyone spying on their passwords, [Haroon] wrote in to remind us that the threat is just as real today as it ever was.

The subjects of his research are touch screen phones and tablets, which utilize on-screen keyboards for data entry. He says that while nearly all password entry boxes on these devices are obscured with the traditional line of asterisks, the keyboards themselves are quite an interesting vulnerability.

Since touch screen technology can be finicky at times, most vendors ship their devices with some sort of key press verification system. On the iPhone and iPad, for instance, each key is highlighted in blue following a button press. This functionality makes it quite easy for shoulder surfers to casually steal your password if you’re not paying attention.

But what if you are well aware of your surroundings? [Haroon] has developed a piece of software he calls shoulderPad, which is based on openCV that does the surfing for him. The application can monitor a video stream, live or recorded, extracting the user’s password from the highlighted button presses. His demonstrations show the recording taking place at a relatively close distance, but he says that it would be quite easy to use surveillance footage or zoom lenses to capture key presses from afar.

He does say that the button highlighting can be easily disabled in the iPhone’s options pane, which should negate this sort of attack for the most part.

Continue reading to see a quick video of shoulderPad in action.

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