Designing A Controllable RGB LED Driver Board

March 30, 2011 by 16 Comments

[Paul] wrote in to tell us about this LED driver board he’s been working on with a few friends. The collaborators had been unhappy with the Lumens per Watt ratings (or lack of a rating) on low powered LEDs and set out to find a better solution. They picked up the beefy ASMT-MT00 which houses all three diodes in one package, with all the pins on one side of the surface mount package, a heat dissipating tab on the other side, and pushed 30 Lumens per Watt. With that in hand they set out to design a host board for the blindingly bright light.

The board includes a heat sink on the underside. To drive the LEDs [Paul] sourced an LM3407 constant current driver. The manufacture recommends using one of these chips for each of the colors in the LED package. [Paul] built a circuit that allows him to route power around each LED, making the system work with just one low-side driver. From there, an ATtiny2313 provides addressable control via the RS485 protocol. Screw terminals on either end of the PCB allow this to be chained along with other modules, and they’ve already worked out a basic PureData program that will be able to address multiple boards once they finish manufacturing them.

Third Time’s A Charm – 512 LED Cube Kicks It Up A Notch With RGB LEDs

March 20, 2011 by 25 Comments

rgb_led_cube

In the comments section of our 512-LED cube post from the other day, several people suggested that to take the project up a notch, building a similar cube using RGB LEDS was the next logical step. It seems that Hack-a-Day reader [vespine] was way ahead of the curve, as he sent us the build details of his 8x8x8 RGB cube shortly after the other story was published.

His cube, which was finished earlier this year, uses 512 10mm RGB LEDs, arranged on top of a simple elevated stand. The stand conceals all of the circuitry he uses to control the cube, the centerpiece of which is a PIC32 MCU. A dozen TLC5940 16-channel PWM drivers are used alongside the PIC in order to adjust the color output of the LEDs, each of which can be addressed and colored individually.

The end result is just about as amazing as you would imagine. He has created several quick demonstration animations, which you can view in the video below. Be sure to stop by his site to see all of his build details – there’s quite a lot there.

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AVR Controlled RGB LED Matrix Plays Tetris

November 9, 2010 by 9 Comments

[Stan] built this LED matrix using a 16×16 grid of RGB LEDs. He built the hardware and wrote some subroutines to randomize the colors. He’s not using PWM because frame buffering is not feasible for the 1k SRAM limit of the ATmega168 he used. Instead, shift registers drive the lights which can be mixed to achieve eight different colors (including off for black) reducing the framebuffer size to just 96 bytes. After he got done with the build he realized this is sized well for a game of Tetris. We’ve seen AVR tetris, PIC Tetris, and Tetris using composite video but it’s always a pleasure to see a new display build.

After the break we’ve embedded [Stan’s] demo video, several pictures, and a schematic. He’s using many of the same principles outlined in our How to Design an LED matrix tutorial.

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RGB LED Headband

October 23, 2010 by 20 Comments

Hard to imagine this going on business trips to Shangai

[Johncon] wrote this fantastic instructible showing us how to make an RGB LED headband. This should come in really handy the next time we find ourselves needing one… it happens. He picked up this little RGB LED strip while on a business trip to Shanghai. He had to reverse engineer the chip that controls each pair, but once that was done there wasn’t much left to do. He’s using a picaxe microcontroller since he had some lying around and, as he points out, they require very little external hardware.

He says he’s going to be ordering more of this LED strip soon and is willing to make a group buy if anyone is interested.

[via MakeZine]

DIY AVR USB RGB LED Notifier

July 6, 2009 by 37 Comments

LED_notifier_in_place

Giving us a chance to break out the TLAs, [Blair] sent in his latest hack where he embedded an RGB LED into his EeePC to display twitter, pidgin, and email notifications. It is based around the ATtiny45, and requires very few additional parts. He based the project on a foundation of work laid by [Dennis Schulze] on notifications and the work of [Dave Hillier] that used V-USB, a library for implementing USB on AVRs. The entire circuit was done freehand and crammed inside the netbook. He says that it is a lot easier to see notifications, even when the laptop is shut.

Related: Email notification via RGB LED

Parts: ShiftBrite RGB LED Module (A6281)

June 29, 2009 by 11 Comments

shiftbriteii

Macetech’s ShiftBrite is a high-power RGB LED coupled with an Allegro A6281 backpack. The A6281 uses three 10bit pulse-width modulators to mix millions of colors using the red, green, and blue elements in the RGB LED. Multiple modules can be chained together for bigger projects, like the ShiftBrite table.

Below the break we demonstrate a ShiftBrite module using the Bus Pirate. For a limited time you can get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.

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Addressable RGB LED Strip

June 17, 2009 by 50 Comments

ledrgb

[Synoptic Labs] stumbled upon an RGB light strip with individually-controllable LEDs. The strip uses 5 volts and is controlled by an HL1606. Because the strips are hard to find, this chip is mostly undocumented and he had trouble driving the strip. He was unable to get it working until he met with [John Cohn], who had previously reverse-engineered the serial protocol. Working together, they released a library for the Arduino to drive the strip. So far, the library only supports fading each LED, the only known functionality. If more strips like these were available, constructing LED matrices would be much easier. Embedded below is a video of the strip fading through the rainbow.

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