These plastic small optic fibre-lit trees were popular about 10 years ago. I purchased two of them, about 5 years ago for around $10 each on sale at a homewares store (B, B&B; if memory serves).

The base of the tree is a plastic "light box" which contains a noisy squirrel-cage electric motor that has an acrylic plastic disc attached to it's shaft, which is printed with lots of colored squares.

There is an MR16-sized 20 watt reflector bulb in the base that shines up through the color wheel to the base of the tree, which is an approximately 1" round bundle of optic fibres. (Fibers if you're in USA, Fibres everywhere else the Queen's English is written).

Some people don't like these trees and find them mildly tacky, but the wife and I have always enjoyed the pretty light show they produce.

There are a few problems:
  • A 20W MR-16 bulb gets hot in the enclosed base, so these can actually cause a fire hazard if there's not adequate ventilation around them. My Mother-in-law had a slightly larger one of these and as she's in Australia, it's hot at Christmas time, and hers actually melted!! It was lucky there was not a house fire. The folks who manufacture and design these in China forget that there is a southern hemisphere.
  • The motor that turns the wheel, at first you don't notice it, but wait until you're in a quiet intimate moment of a movie while snuggling on the couch and the sound of it's constant whirring will drive you mad! And, they get even noisier as they get older and the sleeve bearings and lubricant dry out.
So in this instructable, I want to show you this very simple mod that will give the tree life for many years to come, solve the problems and add the cool features of the LED bulb to it.

Step 1: Start With the Tree Base and the Right Parts and Tools.

Tools you will need:
  • Philips #1 and #2 screw drivers
  • A pair of small wire cutters
Parts you will need:
  • Your 5W RGB MR16 bulb. I got this one from BulbAmerica but you can find them now even at Home Depot or similar hardware stores. You could also try searching AliExpress - there are plenty at low prices.
  • Some longer wood or plastic screws, about 3/4" (or 20mm) by about #4 or #5 (around 2.5-3mm gauge).
Remove the screws at the bottom of the tree base light box. The top half should just lift away.

Step 2: Examine the Base and the Lamps

You will notice the original MR16 bulb is shorter.

The LED one is longer because it includes a significant amount of circuitry inside for controlling it and adjusting the reg green and blue brightnesses. However the diameter is identical.

You need to be sure that the RGB LED lamp will fit. Remember that the color wheel is going to be removed so it's okay for the RGB lamp to be up to that height.

Notice the metal ring bracket used to keep the lamp in place, secured by screws to plastic post bosses.

Step 3: Remove the Motor /wheel Assembly and Replace the Bulb.

This is where the longer screws come in. After unscrewing the motor and color wheel assembly, leave it off to the side and then remove the existing MR16 bulb.

Place the new RGB LED bulb in the socket. Orientation does not matter as these are powered by AC or DC, and the voltage requirement is still 12V just like a normal MR16 bulb.

Affix the metal ring bracket to the top of the bulb and (carefully) use the longer screws to affix it to the post bosses on the base. There will be a gap. DO NOT OVER-TIGHTEN THE SCREWS. We want it to be secure enough to prevent the new bulb from coming loose or wobbling around, but no tighter. It should look like the second picture here.

Step 4: Cut the Motor Wires

Cut the motor wires so the assembly is completely free from the motor and colorwheel.

Cut them as close to the switch and AC power jack as possible WITHOUT cutting any of the other wires. If you make a mistake here you'll have to break out a soldering iron to fix it. If you don't want to do soldering, make sure you cut the correct wires. Look twice, cut once!

You can recycle the motor and color wheel.

The second photo shows what you should have left after this operation.

Notice on the face of my RGB bulb, the small dark dot at 2:00? That's the optical input for the remote control - the IR sensor.

Step 5: Comparing the Width at the Base of the Tree to the Bulb Face

You can see here that the LED bulb-s reflector will align well with the base of the optic fibre bundle.

You can also see that some of the optic fibres will be roughly pointing towards the sensor input on the bulb face - so this means we will be able to remote control the tree by pointing the infrared remote unit at some of the tree's lower branches! How convenient :-)

The final step now is to re-assemble the tree base, put the tree together and plug it in!

For a video of what it looks like: see the youtube video...

About This Instructable




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