30th November
2012
written by Todd Harrison

I wanted to synchronize my GE G-35 multi pattern Christmas lights this year.

I did a full tear down last year of these lights and you can see that (here)

My biggest problem, aside from hating the 14 patterns GE forces on these lights, is that you can’t chain or synchronize multiple strings. So in my case I have two strings starting from a peak with one going left and the other going right. They say in the instructions you can synchronize two sets by setting the same pattern and then turning them both on at the same time. However within 30 minutes the patterns are no longer in sync on the two sides of my roof and that looks horrible.

This is a posting showing how I hacked two strings to use one controller and it is working great. The two strings can never be out of sync, COOL! I know others have done the same so I know this is a sold hack for up to 3 strings in parallel using one control box.

Of course others have gone much farther controlling these lights making their own control boards and adding network connection. I will link to them at the bottom of this posting

Instructions:

To do this hack you cut the ground and data lines going to the bulbs on both sets (don’t cut any power wires which have the faint white printing, see photo). Then terminate one data line coming out of one controller by sealing it in heat shrink. The data line is the middle wire to the lights.

Tie and solder the data line from the 2nd controller to both data lines going to the lights. Then tie and solder ALL 4 of the grounds together so that the circuits have a common ground. The ground is the right side wire when looking at the screw side of the controller box. The ground will be the wire that does not have any faint white lettering on it. Seal everything up with heat shrink.

You still have to plug in all the transformers because the lights need all the power. That’s it and now your parallel strings will always be 100% in sync.

Enjoy the video and let me know if you try this hack and how it works out.

 

photo gallery

CLICK PHOTO for gallery view and click a SECOND time for hi-resolution image. Click thumbnails on low right and lower left of gallery to navigate gallery photos.

 

If you want to go down the rabbit hole more than I did I will keep some updated links below as I find them.

DigitalMisery.com has an open source drop in wireless replace board for these lights. WOW, you can’t ask for more than that. He does not sell the boards yet but keep checking his site to see if he gets a Kick starter going or just follow his open source documents and spin your own board. He links to his code and the Arduino library’s “G35Arduino

DeepDarc.com put up some amazing engineering details on these lights and reverse engineered both the radio protocol and the protocol used on the LED data bus. You must read his post if you’re going to be hacking these lights. He also shares his code and other very useful tips.

Keithsw has some great stuff synchronizing 6 strands and shares his control code, Arduino circuit and a PC software simulator program to help design the layout and patterns.  Here is his short (video).

CheerLights is an ioBridge Labs project that allows people all across the world to synchronize their lights. This sit gives all the hacking details and you can play along even it you don’t have lights by tweeting a color to @cheerlights and watching on ustream.

Jim at Jim’s G-35 Project Page makes his own control board using a PIC18F2620 micro controler.

If I have any of my own hack updates I will link to them from here and under “All Postings” with the title “G35 LED Christmas Light…”

UPDATE 11/11/2012 for EXTRA LINKS:

Good arduino example with new library – (digitalmisery.com)

11/21/2011: Added new Arduino IDE 1.0.1 supported code – (digitalmisery.com)

(codeproject.com

(flippedbits.posterous.com)

(hackaday.com)

(github.com/MarkEMarkEMark/G35-MEO-Programs)

UPDATE 12/18/2012 for EXTRA LINKS:

(mevans77.wordpress.com)

17 Comments

  1. [...] G35 LED Christmas Lights – A Simple Parallel Sync Hack [...]

  2. [...] UPDATE 11/30/2012: My new video “G35 LED Christmas Lights – A Simple Parallel Sync Hack“ [...]

  3. Bill
    01/12/2012

    Had you considered feeding the wires right into the case and soldering right onto the board. Would give you a cleaner look and you could skip both the wire ties and shrink wrap.

  4. 01/12/2012

    @Bill, That would have been a lot more work. Watch my first teardown video on these lights and you will see how much work it is to clean the goo off these water proof boards. Plus I wanted this hack to be something anybody could do and If I started working on PCB’s a lot of people wouldn’t think they could hack their lights.

  5. [...] the light sequences slowly go out of sync after a half hour or so. He came up with a great way to make sure these lights stay in sync that requires only a slight modification. To make two light strings stay in sync, it’s [...]

  6. [...] the light sequences slowly go out of sync after a half hour or so. He came up with a great way to make sure these lights stay in sync that requires only a slight modification. To make two light strings stay in sync, it’s simply a [...]

  7. Bob
    04/12/2012

    I have a string of 64 GECE lights for sale if anyone is interested!

    http://r.ebay.com/PeRG59

  8. [...] an issue with the lights slowly going out of sync. This year he has come up with a way to solve the G35 LED Christmas Light Sync issue with a quick Hack. The two strands of lights have their own controller, you might think to somehow sync the [...]

  9. [...] an issue with the lights slowly going out of sync. This year he has come up with a way to solve the G35 LED Christmas Light Sync issue with a quick Hack. The two strands of lights have their own controller, you might think to somehow sync the [...]

  10. [...] link: G35 LED Christmas Lights – A Simple Parallel Sync Hack VN:R_U [1.9.20_1166]Rating: 0.0/5 (0 votes [...]

  11. JackP
    10/12/2012

    I picked up four sets of Gemmy Industries lights a few years ago. They have great big faux bulbs, with three colors of LEDs in each bulb. There’s a control box at the beginning of each string, and the boxes talk through the string to the next box. Just plug each string into the next and they all stay in sync forever. They’re model 17614 according to the plastic tag, but Gemmy’s website comes back empty when you search on this string. They have a number of strings that simply connect sequentially, with a remote control as well.

    In 2008 they were at http://www.gemmy.com/product.cfm?productId=17614, but that link is 404 now. There’s a video at http://www.youtube.com/watch?v=zmUQOojG6QU&noredirect=1

    http://www.gemmy.com/

  12. gerald
    28/01/2013

    Is it possible to sync a 40-foot string with a 20-footer?

  13. 28/01/2013

    @gerald, In parallel yes, in series no.

  14. gerald
    28/01/2013

    Thanks for a quick response Todd.

  15. gerald
    28/01/2013

    i’m planning on syncing up 3 strings wherein the layout will be 20-40-40 which will give a total length of 100 ft. Do I need to run about 40 feet of parallel lines to connect data and ground to the last or 3rd 40-footer from the parallel junction of the 1st and 2nd string?

  16. 28/01/2013

    @genrald, You can do 3 strings in parallel but you can not run extension. The data lines from the single control box can not be any longer than they currently are to the first light or you will start having delay timing issues. I know this sucks but without hacking in something like an RS-484 data transmission system you’re not going to be able to extend those data lines. RS-484 will extend the data transmission length all that you would need but that kind of a hack takes a lot of electronics skills to build yourself.

  17. gerald
    28/01/2013

    Thanks for the info Todd

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