Summary

I made this as a gift for my wife. It turned out great and looks amazing in the dark!

Instructions

This ornament was designed around the BlinkM MinM Smart LED. I went with a Winter theme and scene, utilizing the LED to really bring it together. The BlinkM is programable, hence the color change and accepts a wide range of low voltages, thus perfect for li-ion power. Warning, the BlinkM will not stop pulling power from the li-ion cell at 2.7 volts. I recommend a li-ion cell with integrated over discharge protection. I have no idea regarding runtime but it has been going strong off and on now for a few months. I really enjoyed making this thing and I hope you do too.

Print and clean case (Ornament Case.skp) and lid (Ornament Lid Only.skp). I painted both these pieces bone to give the appearance of painted wood.
Cut and glue paper to lid. In my Winter design, I printed the message and some accompanying graphics with an inkjet printer. I even poked holes in the paper to simulate snow. Note, the light will appear brightest at the top right corner of the ornament.
Design, buy, create, add, etc., your message and any desired props using super glue. I printed three trees, adding a distanced effect and a star (Ornament Lid Complete.skp). The star was mounted so that it would sit directly in front of the LED and be thus illuminated. I painted the trees green, dusted them with artificial modelers snow and left the star ABS natural because it just looked right.
Insert rocker switch. Careful not to crack the case, it may be tight.
Drill small tap holes for screws and mount battery case.
Mount smart LED. I used a few breadboard headers recessed into the plastic, but I imagine a drop of hot glue would have done the trick.
Solder connections.
Add battery and check height for lid closure.
Drill (if necessary) and add small magnets to the corners of the case and lid. Make sure you have the magnets facing to attract and not repel (Yes, I made this mistake and it sucked).
Fire it up. Receive adoration.

Ingredients:
A. BlinkM MinM Smart LED.
B. CR123 or RCR123 Battery Holder ... with two screws.
C. CR123 or RCR123.
D. Rectangle Rocker Switch ... old computer power supply style.
E. Eight Small Magnets.
F. Imagination ... which you have or you wouldn't be browsing Thingiverse.

Happy Printing. ~ GearsOfWow

Color Changing LED Ornament