Hacking the 100 count LED fairy lights from China

[cubbieco]

So i bought a couple of sets of the LED Fairy lights that you can find on ebay.  Use the buy it now and find ones for about $5.50 including shipping.  These come with a white case & button that you decide how the lights blink.

Unfortunately I found out that the default option on start up is going through and doing everything for a few seconds.  To be useful to me I need them to be steady lit.  So I'm posting the pics of the board in the hopes that somebody else can find some way to bypass the chip.  As an alternative the LEDs are broken in to sets of 33 (or 34) and draw 110? volts DC according to my meter (been a while but it was either 110 or 120).

I bridged the 3 light connections (you can see in the pic) and that got rid of the twinkling but sometimes the lights all fade out as part of the pattern.

As I marked up the pictures though I think I may have figured it out.  Should I be bridging the side of the transistors that is connected to the higher power?  Basically connect the green circles in the picture.  Seems like this may bypass the magic chip and have all lights turned on all the time.  Too late to try it tonight but if it will work this could be a good way to get a cheap set of 100 led lights.  Probably not the best quality but they are bright enough for my needs and for $5.50 anybody could try them.

Thanks for your comments.

[chrisatpsu]

i'd use the 4 diodes to make a full wave rectifier diode bridge, then power the lights so you get both halves of the AC power. (the  bridge is making the power go in one direction, so it's simulated DC. )

double make sure that the led's can handle the 110-120 volts, and make sure it's fused for protection.

diagram of one...
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[rm357]

Short answer - yes.
It is a little hard to see the traces, but it looks like they did a full wave rectifier on the board. For safety reasons, i would go ahead and remove the things that look like transistors. My bet is that they are actully mosfets...

I don't like shorting things like that out. It might feed too much current back through the controller chip. Removing them eliminates that current path.

RM

[chrisatpsu]

i didn't mean use them as they are on the board, i just meant, you could set them up like the diagram, then put them and the fuse inside the smallest size project box.

[urthegman]

VERY interested in this thread!!! I have 10 sets of blue and 10 sets of white that have been useless to me until I saw this thread. Mine are net lights though. The wire on them is more flexible then regular net lights and they rest on bushes like a glove. If a working hack is discovered I would be stoked!!!!!

[SteveMaris]

On the second picture, the solder points with the yellow circles around them need to all be bridged together with a piece of wire soldered in. I have done it to 2 sets of lights, and they have been plugged in, and on since Christmas. (I have them in my greenhouse)
 The blue and white lights look really good. The problem with these lights is they are very flimsy with steel wire inside.
My greenhouse is heated and has a lot of humidity in it. Many of the whites have rusted internally and gone out. The greenhouse is worst case scenario I think as far as conditions, because it is constantly wet and humid.
 If you plan to use these outside in normal winter conditions, I would silicone or hot glue the crap out of the controller box to make it truly waterproof. I will post a couple pictures of what I did....

[SteveMaris]

Sorry for the crappy picture. You can see the wire I soldered in right above my finger, on the eight points across.  A clipping from a resistor would probably be the perfect length. I used a small section of speaker wire I had in the garage. Before someone asks, (everyone does) there are only vegetables and flowers growing in my greenhouse, NOTHING else!  LOL

[urthegman]

So Steve, That's it? That makes them stay steady on? How about dimming? Thanks, George

[cubbieco]

When I had my meter on them the internal dimming was dropping the voltage.  In theory they should dim with an express or whatever.  Been working on an arch today so haven't had time to work on them yet.

[SteveMaris]

So Steve, That's it? That makes them stay steady on? How about dimming? Thanks, George

That's it. They should dim just fine. I do want to reiterate how flimsy these lights are though.  I don't think they can handle a Chicago winter. YMMV

[urthegman]

I agree on the flimsy-ness, I use the blue ones under fake white snow and lexan in my garage to make it look like ice.

[cubbieco]

My plan for them was using them was in some kind of lollipop - land of the sweets decorations from nutcracker once I figure out how I'm going to do it, so once they are in place they shouldn't move much.  I don't think I'd use them for anything that has the potential to stretch anything out.

Shame they don't have stronger cables because the price is right.

[Redstickman]

Thanks for posting this, way back in 2011!

One thing to note when I opened the box:  these wires are indeed very cheap.  They're held in place with hot glue, and when moving the circuit board to access the back of the board, I yanked out one of the glued wires on each light set.  Not a big deal, just something to note, as the connections were so small, I couldn't tell at first which wire got yanked.