Colour Changing LED Christmas Tree

It's January 2019, and I'm just in time for... err.. NEXT Christmas!

The LEDs all start at the same colour but they change colour at slightly different rates. After a few minutes, this provides a lovely random effect. I used a flicker-effect LED with a resistor for the star but, tbh, it just looks like a faulty LED to me!

The body and stand of the tree need to be a minimum 30% fill, for strength. Note that you need to flip the stl for the tree front over, so that the rebated edge is on the top during printing. Do the same for the stand, so that the large flat face is on the deck.

Next, print 21 light beads and one star, at 100% fill (so that there's no infill pattern visible when illuminated). I used clear PLA for these, but I suspect white might work well too.

All the LEDs are a press-fit into the tree front, and simply secured with a dab of superglue as the covers are added. I used 5mm slow changing colour LEDs. They were described as "slow flashing" on eBay but when they arrived I found that they don't actually flash. I'm rather glad of this though, as I now think flashing would have spoiled the effect. If you prefer, you can easily substitute any other type of 5mm LED to suit your own tastes.

Apart from recommending the use of very thin hook-up wire, I won't describe the wiring in any great detail, as it depends on what power supply you're using. I happened to have an old 12v wall-wart available, so I wired the the LEDs in 7 parallel sets of 3 in series - except for the flickering LED which has its own circuit in series with a 1K resistor. Technically this is over-driving the LEDs, so it will be interesting to see how long they last before they burn out.

Push the LEDs in first, then do all the soldering work. To be honest, I never even bothered to trim the leads on the LEDs, as it helped me to keep them in position during assembly. Once you have everything working as it should, THEN glue on the light beads, before adding the tree back cover. I used an assortment of small plastic spring clamps to get everything stuck in the right place. The last part of the job is to fit the stand to the tree, and then declare that the job's a good 'un.

There's ample room for a weight in the base, so if you find it's a bit unstable, just glue something suitable in to add stability. As mine sits adjacent to the wall, I found this unnecessary.

If you want to get fancy; RGB LEDs, with some sort of controller, could look fantastic, but I wanted it to be simple.

So, there you go. At the time of writing, you have just over 11 months to get yours ready for Christmas 2019! So you'd best get your finger out, and crack on!

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October 2019 Updates:

Added version of tree body with clips, to avoid the need for glueing. Some fettling to fit may be required. In my case, I found the use of a small butane heat blower useful to gently adjust these, as my prints came out fractionally over size thanks to cheapo filament.

Added holder for case mounted barrel socket for a neater power connection to unit.

Added "fully enclosed" star to conceal the LED, and for better light dispersion.

Category: Decor