Using OTS lights as basis for DIY

David_AVD

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I've picked up a few sets of Christmas lights over the last few days that should lend themselves to a bit of DIY. I thought I'd detail what I did with each.

The first was the Kmart sets of 8 LED icicle lights. These were on special for $10 per set (down from $19). Each icicle tube has its own micro and 5 LEDs that "drip down" independently of each other. Each clear tube is 15mm x 200mm, spaced 300mm apart and wired back to a 4.5V 500mA plug pack. The plug pack measures 8V with no load, and drops to around 5.5V - 6V when running one set.

I wired 5 sets of them together to give me one continuous section of 40 tubes. This looks so much better than just one 2100mm section of 8. The splice was done near the end of each set and heat shrunk, but you just need to make sure you get the polarity right. There is a limited amount of reverse polarity protection in each tube, so will protect against brief reversals during this phase.

The current draw is hard to measure as the lights are not constantly on, but it seems to be under 100mA for the set. I currently have the 5 sets running off just one of the original plug packs, which doesn't show any signs of overheating. Next year I'll run them of a larger 5V power supply.

The quality of this set seems ok, although a bit of silicone around each cable entry would be a good idea to stop water ingress. You can probably pull the top of the tube (cable entry end) off as it seems to use some sort of hot melt glue.

You couldn't get half the parts together for the price of $1.25 per tube. Even at normal price, that's only $2.40 per tube for a fully assembled product.
 

David_AVD

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The second set of lights I got were a set of 4 candy canes with ground stakes, also from Kmart. These are only 300mm tall and each can has 10x white LEDs. All 40 LEDs are effectively in parallel. The sets are sold as battery operated and come with a battery pack (takes 4x AA cells) which has a switch on it.

I cut the battery pack off, cracked the top of it off and found a 22 Ohm resistor in series with the switch. I then heat shrunk the resistor in-line with the wiring going to the canes. Since I bought 2 sets, I modified both and then spliced the power inputs together and added a long feed cable. Each set is using its own 22 Ohms series resistor.

The total current draw of the 8 canes was 240mA with a 6V supply, which equates to only 3mA per LED. Even at this low current, the brightness is quite reasonable.

Because they've used white LEDs (instead of RED) the canes have more of a pale red / slight pink look to them. I think they would look better with red LEDs. I guess they were trying to show up the white / red striping.

What would be cool to do is rewire these canes with red LEDs and a small PCB to make them controllable. Maybe a tiny DMX receiver in the first one and lesser smarts in the others to make each LED addressable. :)

I'm on the lookout for larger versions as they would be easier to mod and wire up, but have yet to find any at a reasonable price.
 

David_AVD

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My third buy from Kmart was 2 sets (of 4) Christmas solar garden lights for the massive sum of $5 per set (normal price). They are just like regular mini solar garden lights but have red and white striping ! :D

For now, I've just stuck these out in the garden, but I did notice that the plastic ground stakes provided do have the channels (slots) for running wiring in and out of the stems. Hmmmm....

This means that it would be possible to use these solar lights as a cheap housing for some DIY project. The top section (with solar cell, small circuit & LED) simply clips off the clear part and is held together with some small screws. Removing the LED and PCB would take seconds I'd say.

Anyway, the $1.25 per unit price point certainly makes these worth considering as a source of ready made housings.
 

Mike

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Oct 22, 2010
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Rockingham, WA
Thanks for the info David

Was looking at them icicles the other day wondering what I could do with them and now I know.
 

TimW

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Jun 15, 2010
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Melbourne
[attachimg=1]

To the untrained eye.. these are just Bunnings solar garden lights.....
 

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