Introduction: Acrylic LED Christmas Decoration

About: ... using laser cutter, PCBs, 3D-Printer and whatever i get into my hands to build things

Winter is Coming... or calling for decorations.

Since i still have access to a laser cutter in the Fablab Aachen, and enlighted acrylic looks cool, i decided to use acrylic and LEDs again (and having acrylic remnants from the CuckooTankard might have also have influenced the idea :-).

You can also use a dremel or a fretsaw - but the lasercutter is of course far easier to use (at least far less time consuming).

I used 3mm satinized acrylic, normal transparent acrylic should also be fine (for one snowflake i tried an expensive opal one - looks nearly the same).

Additional you need a soldering iron, wires (isolated and thin bare silver wire), some resistor (e.g. 18 ohm if you use 6 leds with 2 mignon cells - could be even smaller: Resistance = (3V - 1.9V)/20mA), the corresponding batteries and batterie holder and either bright 3mm LEDs or - as another variant, because using only normal LEDs would be boring - bare WS1812B LEDs. For the latter you will need an Arduino or MSP430 launchpad for controlling and also some capacitors (e.g. 100 µF) if you use long wires.

In this instructable i will first give the design files - some complete or at least the cutouts for the LEDs (or/and hints/links to make your own if i used graphics from the internet), and the different building steps for a snowflake with a 3mm LED, and for the variant with a WS2812B LED. Building the (sort of 2.5D) angel and the christmas tree are described later and the last step will cover the Merry-Christmas-sign shown in the middle.

I hope it is understanable and you enjoy it!

Otherwise thanks for reading (especially of course if you favour/vote/comment :-)

Step 1: Designing

Depending which LEDs you use you need different cut outs. The basic cut outs for 3mm leds and a coincell, just the 3mm LED ring and the WS2812B ring are found in the Cutouts-files. These can be inserted in snowflake vector graphics either made by yourself or just downloaded from the internet. I drawed one after a photo from a nice papercut snowflake (see the Snowflake-files), sadly i didn't bookmarked the side.

The other snowflakes which you see on the first page are made from the nice vector snowflakes - just add the cut outs for the leds and - if necessary - modify the graphic slightly.

The tree on the other hand is made from two simple tree shapes which are pinned together (Tree-files).

If you want to use the sign files for the Merry-Cristmas-Tag (you can of course write something different), you will need to install some nice fonts first: Soft Ornaments Three, Bodoni Ornaments and Medusa.

If you want to build an angel: Again the internet is your friend - i used a dancing girl and wings, added to 5*3mm boxes as connection holes on the body and modified the wings (adding a 3*5mm addon with round end on connection with the body). Add e.g. two cut outs for LEDs on the legs pointing upwards.

After finishing your design, you are ready to cut.

Step 2: Lasercutting

After making the layouts, laser cut the acrylic. I removed the upper protection foil before and the lower after cutting (to protect the acrylic from dirt on the laser cutter grid). Since the laser cutter did all the work, not very much to describe here.

Step 3: LED Part 1 - Bright 3mm Type

First bend each leg of the LED in a 90° angle and insert them into the cutout. Just make sure that the anode and cathode of each LED points allways in the same direction. Mark them with a edding before bending - this makes things easier.

Then bend each leg on a side towards the neighbour, wrap it around it and fixate them with solder. Cut off the rest of the leg - but if you use a coin cell in the middle (see next step), keep the last leg as battery connector.

Step 4: Coin Cell Powered

If you use the variant with a coin cell in the middle: Bend the legs from the last LED in a u-turn as a battery connector over the battery hole. Insert the coin cell, press the LED legs on it and fixate it with adhesive tape.

Step 5: External Battery

If you don't use a coin cell, you solder two wire on the legs. Twist the wires and solder a battery holder at the other end (Don't forget to add a resistor between wire and battery holder corresponding to the input voltage).

Step 6: LEDs Part 2 - WS2812B Type

More fun with intelligent LEDs:

Insert WS1812B LEDs in the sqare holes - the sides with the solder pads should look upwards/downwards (otherwise it will not fit). Make sure that each LED is inserted the same way (look at the marked pad - a small triangle edge at the top side of the LED marks the ground pad).

Solder a thin silver wire at the neighbour of the triangle-marked pad (the Data-In pin, the datasheet is your friend) and thread it through a hole of the snowflake to the other side. Find the Data-Out pin of the neighbour - this should be the nearest pin of the next LED. Solder the wire on the pad and cut the wire. Continue with the next Data-In pin until all LEDs are connected.

Connect the ground pads of each LED on one side with the wire, and do the same for the VCC pads.

Solder three (isolated) wires on the ground, VCC and until now unconnected last Data-In pad.

Step 7: Connect WS2812B With an Arduino...

...or another micro controller: VCC to 5V, ground to GND and the Data-In pin e.g. to pin 6. Twist the three wires (for a better look), install the Adafruit Neopixel library and upload the strandtest example or your own code.

If it didn't light up the wires might be to long - add a capacitor between VCC and GND on the snowflake (which might be also better to protect the LED from burnout).

Ready for: Oooooh shiny lights :-).

Step 8: Making an Angel

The two laser-cutted wings should have a 5mm extension for insertion in the body. Clamp this part and heat the wing up with a hot air gun. After a while you can bend the wing behind this extension in a 45° angle.

Insert both wings (hopefully both are bent in opposite direction) and e.g. two LEDs in the legs. The wire follow the outer form of the body up to the arms to the hands, where they form an kind of bracelet (one leg/side/arm for positive, the other for negative voltage).

The main problem was mounting the cable: On the arm it looks like hand cuffed, around the neck was even more strange (or more precise: strangled :-), and making a hole in the head... well, not so nice either.

Luckily it turns out that the gravity point was low enough that soldering the wires on the side and move the wires between the wings upwards works fine.

Step 9: Christmas Tree

Classic build: Two shapes pinned together. Just add the led on the shape with the cut-out for the second shape on top and the whole LED cutout at the bottom before assembing the tree. If you insert the second shape from above, bend the lower part a little bit such that it slides downwards (vertical) beside the LED. When both shapes are aligned, you can then bend the lower part straight - the led cut out allows then a horizontal sliding above the led.

The four pads of the WS2812B are still accessible. Solder a thin silver wire on each pad and cut them at the top of the tree, where isolated wires are soldered on. Glue the silver wire on the tree to fixate them, then twist the isolated wire and connect ist with the micro controller.


Step 10: Final: Merry-Christmas-Sign

Two WS2812B LEDs inserted on opposite sides of the sign - not my best idea.

One silver wire can go along the lower edge of the sign (e.g. ground, the "triangle-pad"), another along the upper edge (VCC, the opposite pad). Both of them build a kind of additional frame. Still one wire missing - Connect Data-In from one WS2812B with the Data-Out of the other with one wire straight above the backside of the sign.

Add again three isolated wire at VCC, GND and the free Data-In pad of one LED - i soldered the last one first on the middle line because it looks so beautiful symmetric... but of course that didn't work.

Power up. Of course the basic example with different colors for each LED is not very useful for this design, but still - Enjoy!

And if you kept up to this step - special thanks for reading again.

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