G-35 circuit board porn

[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.

Comments

  1. Mike says:

    *fap* *fap* *fap* *fap* *fap* *fap*

  2. cmholm says:

    Unfortunately, my local big boxes aren’t carrying the G-35, so I’ve nowhere to await the post-season discounting.

  3. DvD says:

    Totally semi-related… I am infatuated with those LED icicle lights that ‘drip’. Might anyone have any info on how to replicate those cheaply? Don’t need to encase them in plastic- just the circuit.

    • Bigdeal says:

      Oh, I love them too!

      I just saw these at the mall today… The model I saw had a crystal-clear casing, so I could see what appeared to be a small 8 pin microcontroller, on top of a 1×10 array of SMD led’s.

      If you’re just interrested in making the same circuit, then with charlieplexing, it’s quite easy to cycle say 20 LEDs with 5 pins of a typical attiny13. there are plenty of articles about charlieplexing on this site.

      I hope this helps a bit with your question!

  4. Robert says:

    That was the most interesting thing I have ever seen about a single strand of Christmas lights. I doubt he is the type of person GE had in mind during design. Does he really think people are going to see these elsewhere and not want to buy them? Most people don’t care enough to ask the home owner what model of lights they have. They don’t even care to pick them over in the store. They’ll just grab some lights that they looked at for a good 30 seconds. The phrase “over thinking” comes to mind when watching the video.

  5. Mike says:

    The processor is an 8051 derivative.

  6. Microguy says:

    I posted this on his site, but I’ll duplicate it here.

    Actually, I think you can sync the lights, without replacing the chip or adding a crystal.

    You need to do two of at least three things.

    1. Find a “code” that can be sent down the lights control line, that does nothing.

    OR

    2. Find a code that you can use, if they’re all used (say 32 code are there, but they’re all used).

    And, in the second string, you would have to watch that line, interrupt or what ever, and reset your timer on that.

    So you have two different processors, running almost in time code.

    Of course, it’s not perfect, but it’s not “run away” either, because you’re continuously resetting the sync. So it may be off a couple clock cycles, but won’t wonder far from that.

    (think of those “atomic clocks” that receive the time signal. It’s not perfect, but the clock is always right)

  7. Rob says:

    Looks like quite a few jumper terminals on the board, of which only a few (e.g. JP6 in one of the photos) are populated with zero-ohms. Might be fun to see what changes when shorted.

  8. Sprinklegenie says:

    Anywhere to get these in the UK for a reasonable price?

  9. John Otken says:

    Did I miss where “you can now buy a drop-in board”? I don’t think that Paul has put his ColorNode board on KickStarter yet.

  10. Cliff says:

    I’ve seen similar lights at our local Home Depot, albeit with a sealed box at the end and just 12 lights in the string, possible that these are a variant? mind you there’s no remote with these…

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