Accidental LED Fabrication

December 28, 2010 by Mike Szczys 36 Comments

[Grenadier] had a piece of silicon carbide sitting around that he planned to use when making a primitive diode called a Cat’sWhisker Diode. While probing he noticed that one of the crystals threw off a bit of light. He popped it off and used JB Weld to attach it to a brass plate. The peculiar thing is that it generates light when power is run through it both forward and reverse biased. So what’s going on here? According to an informed discussion on the phenomenon there’s actually a pair of diodes in series but with their polarity reversed.

LED Lighthouse Simulator

December 27, 2010 by Mike Szczys 11 Comments

This Christmas [Bill Porter] decided to show his parents that those college dollars were well spent. He upgraded the custom lighthouse light which he originally designed in high school for their garden fountain. He even went so far as to craft some retail-worthy packaging for the gift.

We think it’s a wonderful design, on a custom PCB and based around an ATtiny85. A real lighthouse has a spinning lens to aim the beam of light. When the lens sweeps across your viewpoint there is a sudden flash and he’s recreated that effect using PWM. Take a look at the video after the break and you’ll see what we mean.

Also, during development he was plagued by a startup glitch which we got majorly sidetracked reading about. Continue reading “LED Lighthouse Simulator” →

Didn’t See The Lunar Eclipse, Make One!

December 22, 2010 by Greg R. Jacobs 5 Comments

Lunar eclipse simulator

Last night was a lunar eclipse meaning that most people would have been out gazing up at the sky watching it. For some the eclipse evaded them using cloud cover, but instead of giving up, they got innovative. [Garrett] decided to build a moon simulator to keep track of the eclipse using a few spare parts and some quick code. The parts that were required for this project includes an Arduino UNO, a singular ShiftBrite Shield, a ShiftBar, ChronoDot and a Satellite Module 001. This is the perfect project for the Arduino to be used in because he had to toss it together very quickly and it is meant to be a temporary solution. If he were to make this permanent, we would guess that he would make a smaller and more cost effective version of the electronics. He documents his experience on Macetech.com in more detail and the outcome is pretty amazing. Code is yet to be posted but hopefully it is forthcoming soon as well as a video of the simulator working.

Hacked LED Christmas Lights

December 1, 2010 by Devlin Thyne 35 Comments

[Robert] wanted more out of his GE Color Effects G-35 LED Christmas lights. He reverse engineered and then hacked the protocol the lights use to communicate so that he can control each bulb. A 26-bit frame contains a 6-bit address, an 8-bit brightness value, and a 12-bit color value. The daisy chain topology of the data bus allows for modular bulbs with addresses enumerated during the startup of the string of lights. With this information, a 5 volt capable microcontroller is able to control a whole string of these lights with a refresh rate of up to 24Hz. In this case, [Robert] used an ATtiny13A microcontroller to control the string of lights. You can see a video of them in action after the break.

Also taken apart and analyzed, were the wireless transmitter and receiver that came with the lights, revealing a cheap ISM band receiver and transmitter module pair. Perhaps they will be useful for another project. We look forward to seeing people put these hacked lights to use throughout the year.

[via Make]

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DIY OLEDs

November 29, 2010 by Devlin Thyne 43 Comments

[Jeri Ellsworth] has put together a couple of videos that cover how she made her own organic light emitting diodes, or OLEDs. In the first video, after the break, it discusses the difference between regular, rigid semiconductor LEDs and organic LEDs. The video then goes on to show how to make an OLED as successive layers of materials. Indium tin oxide (ITO) on glass forms a transparent anode. That is then coated with PEDOT:PSS, a conductive polymer mix that is used as a hole transport layer. Then a red diamond ruthenium complex is added to create the emissive layer. The cathode layer is a low work function metal, initially, gallium indium eutectic alloy then later other metals were shown to work. The second video, shows how to juice a glowstick and make OLEDs with the liquid. The dye in blue glowsticks, 9,10-Diphenylanthracene, is an organic semiconductor and will emit light as an electric current is passed through it. The glow stick method seems to have some problems as the ITO coated glass plate is degraded by the glowstick chemicals. It would be interesting to see if using the porous aluminum or similar technique from [Jeri]’s flexible electroluminescent displays could be used as an electrode.

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Audio Controlled Party Lights

November 28, 2010 by Mike Szczys 15 Comments

[Thibault Brevet] wanted his own party lighting that pulsed and faded along with the tunes. He ended up building a system based on an Arduino and a PC running Processing. The output from a mixing board is fed into a PC and measured by the Processing script. From there, the calculated light levels are sent to the Arduino to address the LEDs via the control board seen above. [Thibault] built four LED modules that each have two 4-channel LEDs (red, green, blue, white) separated by a few feet. This means 32 PWM signals are necessary to drive the system. To get there, he utilized a pair of TLC5940 16-channel PWM chips, which function like cascading shift registers but have some fantastic current limiting and dot correction features. Take a look at the demo after the break to see what he’s accomplished.

The TLC5940 is a popular choice for driving RGB LEDs, and would be a nice part to use if you decide to make yourself a Ping Pong LED Wall.

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LED Wall And Kinect Join Forces

November 21, 2010 by Mike Szczys 11 Comments

[Alex] wrote in to let us know about this Kinect controlled LED wall that was whipped up at the Tetalab hackerspace in Toulouse, France. The wall, which was built earlier in the year, uses some MAX7313 LED intensity controlling shift registers. Each gets its own board and controls the intensity of sixteen different red LEDs. They’re embedded in the wall module and covered with ping-pong balls as diffusers.

The recent activity on the project takes advantage of the Xbox Kinect. As you can see in the video after the break, they’ve used the open source Kinect drivers to capture 3D environment data, processing it into color gradients which are displayed on the Pong wall. Shouldn’t be long before they someone comes knocking on their door to install this in a dance club. We love the effect, especially because it works in a dark room and the LEDs don’t cause any interference with the video capture.

Continue reading “LED Wall And Kinect Join Forces” →