G-35 Circuit Board Porn

November 29, 2011 by Mike Szczys 13 Comments

[Todd Harrison] took a slew of pictures in his quest to loose all the secrets of the G-35 Christmas Lights. These are a string of 50 plastic bulbs which house individually addressable RGB LEDs. We’ve seen a ton of projects that use them, starting about a year ago with the original reverse engineering and most recently used to make a 7×7 LED matrix. But most of the time the original control board is immediately ditched for a replacement. It’s become so common that you can now buy a drop-in board, no hacking needed. We enjoy the hard look that [Todd] took at the electronics.

The stock controller uses a single layer, single sided board. There’s a resin-blob chip, but also an SOP-20 microcontroller. Since [Todd’s] using several strings of lights on his house, he wondered if it would be possible to improve on the controller in order to synchronize the strands. His investigation showed that the board was designed to host a crystal oscillator but it is unpopulated. Unfortunately you can’t just add those parts to improve the timing of the chip (firmware changes would also be requires). He found that there’s a spot for a push-button. Quickly shorting the pads cycles through the effects, shorting them for a longer time turns off the string of lights. There is wireless control, but it seems that the only functionality it provides is the same as the unpopulated switch.

We enjoyed the close-up circuit board photos, and we like the spacing jig he used to attach the lights to his fascia boards. We’ve embedded a lengthy video about his exploits after the break. Continue reading “G-35 Circuit Board Porn” →

G-35 Christmas Lights Do Make A Great LED Matrix

November 7, 2011 by Mike Szczys 16 Comments

This fully-addressable RGB LED matrix was built by [John Graham-Cummings]. He didn’t start from scratch, but wisely repurposed a strand of GE Color Effect lights and built a pleasant looking case in which to mount the G-35 hardware.

We’ve seen this hardware used in a similar way before. Because each ‘bulb’ has its own microcontroller, color data is shifted in via a serial bus. Orient the modules in any pattern you choose and account for that layout in software.

Since the strings have 50 bulbs, [John] simply cut off the one on the end to form his 7×7 matrix with the remaining 49 units. A square of plywood with a grid of holes holds each in place. Cord mess is not a problem as the extra was cut out and the remainders were soldered together again. [John] uses an Arduino Pro to feed in the data, which you can see for yourself in the clip after the break.

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Scrolling Marquee Made From GE Christmas Lights

January 11, 2011 by Mike Szczys 23 Comments

[John Riney] picked up three strands of addressable Christmas lights and used them to make a scrolling marquee. You may remember that the G-35 lights were hacked at the beginning of December, and we saw a project or two that involved these fun toys.

In order to make the display [John] modified the original packing material to hold three strands in a six by eighteen grid for a total of 108 pixels. In the video after the break he points out one interesting feature of the strand that we don’t remember from looking at the original hack; each bulb’s address is not fixed, it can be set after power-up. This works the same way as sending color data, except that you just send the address. This makes controlling a grid like this extremely easy from a microcontroller programming standpoint. Once all of the addresses have dropped down the serial bus, you’re ready to start sending color and intensity data packets.

The setup is fast, bright, and beautiful, taking just three pins of an Arduino for control. The only thing holding us back from trying this ourselves is the $150 price tag. But that was before the holiday, and we have heard some whispers about closeout deals on this product.

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