Instructables
7 LEDs make a christmas tree.

If you can solder a little, you can make a christmas tree without hurting any trees. It takes 7 LEDs, some wire and a battery. That's it.

The video below features some LED Christmas Stars as well. The making of the Stars is covered in a separate Instructable.

No video playing? Have a look at it here...

So get your soldering iron, grab your LEDs, find some batteries and kick off the christmas decorating season.

If you're uncertain about your soldering skills: Start with making the star (over here). It's easy. You can do it. Really. Trust me.
 
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Step 1: Stuff and tools

For a christmas LED tree you need:
  • 6 green LEDs, 5mm dome
  • 1 red led, 5mm dome
  • 10cm of thin copperwire, insulated.
  • Optional: 120 Ohm resistor
All parts for the star and the tree can easily be ordered at RadioShack, Mouser (if you live in he US), or Farnell or Conrad (Euro's, Aussies, rest of the world).
If you're new to electronics: buy a assortment of LEDs like this one.

Costs:
The tree costs about €2,- / US $2,60

Tools and other stuff needed:
  • For a template: 5mm plywood or something similar.
  • Soldering iron and solder
  • Pliers or pincers
  • Polymer clay or a third hand to fix parts for soldering
  • Multimeter for debugging

Step 2: The circuit of a LED Christmas Tree...

Picture of The circuit of a LED Christmas Tree...
The Led Christmas Tree's circuit consists of three separate circuits, all connected to the same battery:
  • On the left side of the tree: 3 green LEDs in a row (that is, in series).
  • On the right side of the tree: 3 green LEDs in a row.
  • On the top one red LED.
The switch in the circuit is not a physical part of the tree: The tree lights up by planting a wire into the plus-connector of the battery.

What can go wrong?
The easiest mistake to make is connecting the LEDs in the wrong "direction". Have a look at this I'ble (step 2 is about LEDs) if you're not sure about LEDs having a direction...

Here's the family of US powered LED trees (and one star) I made to spread around the office (I brought them together for the picture). I made spiral wires as shown to connect to the top LEDs. Soldering to these spirals was a bit clumsy though.
IMG_5688.jpgIMG_5679.JPGIMG_5681.JPG
ynze (author)  masynmachien1 year ago
Owww cool! The helix is a nice touch! All trees are usb-powered?

You totally deserve a 3 month pro membership for the pics, but my guess is you have plenty of those...
Yes, they are all USB powered.

Indeed I have plenty of pro membership codes.

Thanks.
Brosiman1 year ago
Very nice and simple project!(en kerst ledjes zijn beter dan kerst liedjes ;) )
ynze (author)  Brosiman1 year ago
Thanks, glad to hear you like it. Kerst ledjes forever!
davidkichi1 year ago
Awesome! Btw, what does a resistor do in this case if it were to be used? Thxs
ynze (author)  davidkichi1 year ago
It limits the current through the LEDs, so the battery lasts longer. The LEDs will be dimmed a little, though...
these are so simple and cute! love it
ynze (author)  amandaghassaei1 year ago
Thanks!

(Omitting resistors is a bit of a crime for some electronics-gurus I know, but it makes the making and looks so much fun ;-) I'll add a circuit that is a bit more electronics-political-correct one of these days...)