LED Hacks

1943 Articles

Open Garage Door Indicator

September 26, 2009 by 49 Comments

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How many times has this one happened to you? Just coming home from work, you walk in from the garage, settle down, and pick up the newspaper. But wait, did you remember to shut the garage door?

Presenting the open garage door indicator. [xjc2010] chose the simplest circuit possible, using only a switch to turn on and off the setup, an LED acting as the signal, and a transformer/resistor combo to drop the voltage to an acceptable LED friendly 2.8 volts. We don’t like how he strung wire all over his house to place the beacon, and would have preferred something wireless in one way or another, but for under 6 bucks this gets the job done quickly and cheaply. Now if only we could get it to remind us if we turned off the oven while on vacation.

[thanks Craig]

Introduction To FTDI Bitbang Mode

September 22, 2009 by 80 Comments

It was an interface that launched a thousand hacks. Near trivial to program, enough I/O lines for useful work, and sufficiently fast for a multitude of applications: homebrew logic analyzers, chip programmers, LCD interfaces and LED light shows, to name a few.

Today the parallel printer port is on the brink of extinction (and good riddance, some would say). Largely rendered obsolete by USB, few (if any) new peripherals even include a parallel connector, and today’s shrinking computers — nettops, netbooks, media center PCs — wouldn’t have space for it anyway. That’s great for tidy desks, but not so good if you enjoyed the dirt-cheap hacks that the legacy parallel port made possible.

Fear not, for there’s a viable USB alternative that can resurrect many of these classic hacks! And if you’ve done much work with Arduino, there’s a good chance it’s already lurking in your parts drawer.

Continue reading “Introduction To FTDI Bitbang Mode” →

BlokClok – Abstract Time Display

September 21, 2009 by 13 Comments

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Clocks made from blinking LEDs always make for fun projects. [Earthshine] built a clock that displays time abstractly using an 8×8 RGB LED matrix. The video embedded after the break illustrates how to read the time but here’s the gist of it: One LED is illuminated in the outside box of LEDs and moved in a clockwise motion to approximate seconds. Inside of this, there are four quadrants; upper left indicates hour-tens digit, upper right hour-ones, lower left minute-tens, and lower right minute-ones. This certainly makes for an interesting conversation piece!

There is no schematic and no code available but it’s really the concept that we’re interested in. If you must know, [Earthshine] bases this build around an Arduino. A DS1307 real time clock keeps the time, while four 74HC595 shift registers are utilized to control the three LED colors and the multiplexing.

Continue reading “BlokClok – Abstract Time Display” →

Wireless RGB Light Bulb

September 20, 2009 by 15 Comments

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Want to make the above yourself? [Sprite_tm] did a thorough job documenting the build step by step (complete with pics, schematics, graphs, and links to the parts used). In summary, [Sprite_tm] busted open an Ikea CFL bulb to reuse the housing. Inside, he installed a scavenged power supply, ATtiny44, RGB LED module, and a radio receiver. A remote control allows [Sprite_tm] to change the lighting of his room to nearly any color. The cost of the project is a little under $30. The price tag isn’t so steep when one considers the insanely long lifetime of LEDs.

Web Controlled Dark Crystal

September 19, 2009 by 11 Comments

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[Reza] sent in his mood rock. Unlike other “mood” devices, instead of showing what mood you’re in, it shows what mood the internets are in. Two ShiftBrite modules are controlled by an AVR ATmega8 which then connects to a computer via USB. The assembly is placed inside of a piece of alabaster.

USB communications are controlled by the ATmega8 running V-USB (formerly AVR-USB) firmware. [Reza] wrote some code to control the colors from the web using Perl and AJAX. Head over to the web interface to set the colors yourself. We’d love it if a live webcam was added so we could see our mood on the rock itself. Continue reading “Web Controlled Dark Crystal” →

Software Pulse Width Modulation

September 17, 2009 by 11 Comments

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Pulse Width Modulation is a topic that tends to give a lot of beginners trouble. [Daqq], whose nixie plasma ball we covered a few days ago, has a simple but effective PWM project that you should take a look at. The circuit used 9 LEDs clustered together into 3 sets of RGB modules and connected them to an AVR ATtiny2313 through some current limiting resistors. Most of the time the PWM function of the AVR’s timers would be used to generate the signal but this application calls for 9 signals which is more than can be produced by this chip. The workaround is to generate the signals using software PWM. Continue reading “Software Pulse Width Modulation” →

Router/Twitter/Arduino Clock

September 16, 2009 by 56 Comments

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[Kyle] decided to build the above LED clock for his church. Though it may look impressive enough, it is also hiding loads of features. [Kyle] wanted to make the clock as easy to control as possible, so rather than use buttons or dials to control what is being displayed, he used Twitter. The clock is connected to the internet through a Linksys WRT54GL. The router was hacked so not only does it supply the connection to Twitter, it also parses all of the replies the clock’s feed gets. The clock responds to commands to turn it on or off, run a countdown before service, display the number of viewers on the church’s live stream, and display a sequence of numbers. The time never needs to be set, as it is synched from the internet. The circuit for actually driving the display is based off a PIC, but it was changed to run off an Arduino.