WS2812b Ambilight Clone For The Raspi

March 26, 2014 by Brian Benchoff 28 Comments

For how often the Raspberry Pi is used as a media server, and how easy it is to connect a bunch of LEDs to the GPIO pins on the Pi, we’re surprised we haven’t seen something like Hyperion before. It uses the extremely common WS2812b individually controllable RGB LEDs to surround the wall behind your TV with the colors on the edges of the screen.

One of the big features of Hyperion is the huge number of LEDs it’s able to control; a 50 LED strip only eats up about 1.5% of the Pi’s CPU. It does this with a “Mini UART” implemented on the Pi running at 2MHz.

There’s only one additional component needed to run a gigantic strip of RGB LEDs with a Pi – an inverter of some sort made with an HCT-series logic chip. After that, you’ll only need to connect the power and enjoy a blinding display behind your TV or monitor.

Thanks [emuboy] for sending this one in.

Companion Cube Christmas Lights Improved With Neopixels

February 20, 2014 by Brian Benchoff 3 Comments

cubes

[Crenn] obtained a string of official companion cube lights from Valve, but being in Australia couldn’t put them to their non-judgemental glory without the use of a step down transformer. They sat on the workbench for a few months until an idea was hatched: replace the bulbs with an Adafruit Neopixel strip, making these wonderful inanimate friends a string of individually addressable RGB LEDs.

The process of converting these cubes required stuffing a very small 9.4mm PCB inside. This PCB was designed in KiCAD thanks to a few classes at the Melbourne hackerspace. The board files were sent off, PCBs received, soldered up, and stuffed into the cubes.

Control is via a Duemilanove with a single IO pin using the Neopixel library. All the code, board files, and schematics are available on the gits. Future improvements might include a 3D printed cable relief and a way to securely mount the PCBs to the inside of the cubes.

Video available below.

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Rewriting WS2812 Driver Libraries For Optimization

February 2, 2014 by Mike Szczys 14 Comments

ws2812_compared

We like [Tim’s] drive for improvement. He wrote a WS2812 driver library that works with AVR and ARM Cortex-M0 microcontrollers, but he wasn’t satisfied with how much of the controller’s resources the library used to simply output the required timing signal for these LED modules. When he set out to build version 2.0, he dug much deeper than just optimizing his own code.

We remember [Tim] from his project reverse engineering a candle flicker LED. This time, he’s done more reverse engineering by comparing the actual timing performance of the WS2812(B) module with its published specs. He learned that although several timing aspects require precision, others can be fudged a little bit. To figure out which ones, [Tim] used an ATtiny85 as a signal-generator and monitored performance results with a Saleae logic analyzer. Of course, to even talk about these advances you need to know something about the timing scheme, so [Tim] provides a quick run-through of the protocol as part of his write-up.

Click the top link to read his findings and how he used them to write the new library, which is stored in his GitHub repository.

Arduino Xmas Tree Shield

December 18, 2013 by Kevin Darrah 12 Comments

christmasshield

Nothing reminds us that it’s the holiday season more than an LED Christmas Tree submission. This obviously is not the first of its kind, but [Jose] does offer up a new technique using addressable RGB LEDs.

[Jose] decided to use 20 WS2812B RGB LEDs, which if you haven’t seen before, are RGB LEDs with an integrated controller. Yep, that’s right, just power/ground and 1 data line is all that is needed to control hundreds of RGB LEDs. This LED tree’s design is simple: a custom-etched PCB cut it in to the shape of a Christmas tree. The WS2812B LEDs helped keep everything clean, so the tree lacks any ‘ugly’ ornaments, except for the required bypass cap here and there. For an added bonus, the tree’s LEDs are synchronized to music generated by an Arduino via a piezo buzzer. Why is it a shield? Well, the whole tree plugs in nicely to a standard Arduino interface. This looks like the perfect starter project to familiarize yourself with addressable LEDs, or at least to get you warmed up before building your own infinity portal.

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Backlit PCB Panel As Wall Art

September 24, 2013 by Mike Szczys 6 Comments

For his buddy’s wedding [Saar Drimer] wanted a one-of-a-kind gift, and what’s more unique than a piece of art? He set out to design something that would speak to his geeky game-loving friend. This full-panel PCB is what he came up with. It’s a wall hanging that uses addressable LEDs and a PCB for the enclosure and as a diffuser.

On the right you can see the panel as it was delivered to him. He used routed slots to separate the main body of the enclosure from the four side pieces and the mounting bracket. This design lets him snap off the parts and solder them in place. The only thing you need to add to it is a pair of screws (well, and the components that make it light up).

We’re shocked by how well the PCB works as a diffuser. The substrate is translucent when not covered with silk screen or the copper layers. The outline of the letters uses that, as well as circular areas along the side pieces. The letters themselves are copper fills that have artistic patterns removed from them. This really adds to the visual appeal when the piece is illuminated by 42 WS2812B LEDs. The video below shows the piece in action. It really takes PCB as art to the next level

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