While tinkering around with some RGB-Leds which I didn´t needed when building an Ambilight for my home cinema, I got the idea for building these coasters for lighting up some bottles of booze standing on my shelf.
In fact the one shown in this instructable is not the first one i built as I had to make some improvements compared to the original prototype.
The coaster features 8 RGB-Leds each one driven by a WS2801 driver chip which is controlled by an Arduino Pro-Mini.
Step 1: Materials and Tools
For building the "main parts" of the coaster I simply used pieces of wood which were leftovers of former projects, feel free to substitute the top and the bottom panel by any kind of wood you like if you could get it into the right shape.
Wood and similar:
Top panel: Plywood with black structural coating 110mm*110mm*9mm
Bottom panel: Plywood 110mm*110mm*6mm
Sides: 4 Bars of 110mm*10mm*10mm with ends cut in 45° angle
As cover for the top panel I used plexiglas with a thickness of about 3mm in the same size as the panel (110*110mm)
4 self-tapping screws (3*12 Spax for example)
4 "nice looking" screws of any kind (I used some that came with my PC-Tower just because I liked the optic)
For the electronic part you will need:
1* Arduino Pro Mini (could be easily found on Ebay)
aprox. 24cm (8 Led´s) WS2801 LED-Strip or similar
1* 2,1mm DC-Barrel Jack
some angled Pin-Headers
some kind of thin copper wire
Arduino FTDI Breakout or Programming Board
Electric drill and drills (5mm and 3mm)
60mm holesaw or jigsaw
Step 2: Building the Frame
At first, cut all wooden pieces into their designated sizes.
Then cut a hole into the top panel with about 60mm diameter, this can be done either by using a holesaw of that size or by hand using a jigsaw.
After that, make sure to sand all edges to remove splinter to avoid injury.
After you finished the individual pieces glue the four wooden sticks to the top panel as you can see in the picture
Step 3: Preparing the Plexiglass
While the glue dries we will start working on the plexiglass cover for the top panel.
Be careful while working with plexiglass as it is a pretty hard material it tends to splinter or to get cracks.
At first cut the plexiglass into the right size (110mm*110mm) by either using a desk-mounted buzzsaw or a jigsaw.
After that, you have to drill the holes for the screws which hold the plexiglass in place.
Place the holes about 1cm out of each corner, choose the drill size according to the screws you plan to use, in my case a 5mm drill did the job.
Step 4: Fitting the Plexiglass
After the glue has dried, put the plexiglas onto the top panel, center it, and fix it with tape.
Now use the same drill you used for drilling the holes in the plexi to "mark" the positions of the holes on the top panel, this could also be done by marking the holes with a pencil.
Then use a smaller drill to drill the holes into the top panel to make fastening the screws easier.
Now use the screwdriver to bolt the plexiglas on the top panel. Don´t forget to remove the protective film from the back of the plexiglass before doing so.
Step 5: Preparing the Bottom Panel
First, drill some holes into the bottom panel to bolt it to the top part.
Put the wholes about 5mm out of each corner so the screws go directly into the frame of the top part. Use a drill fitting the size of the screws you want to use (5mm again in my case).
Now, cut the Led-Strip into 4 pieces of 4 Led´s and stick them onto the bottom panel. Then glue the Arduino port onto the panel as shown in the picture.
Step 6: Putting Together the Electronics
After that, use some thin copper wire to connect the leds among each other and to the arduino.
Be careful to not mess up with the data an clock lines of the WS2801 chips, because if connected in the wrong way they simply won´t work.
Also be careful when using cheap arduino clones as mine, as you can see I tried attaching the data and clock line to pin A6 and A7 which unfortunately didn´t work. So I changed them to Pin 9 as the Clock pin and Pin 12 as the Data pin.
Next add two wires for powersupply which connect to the Led´s as well as to the GND an RAW pins of the Arduino.
To finish the soldering, add some angled pin headers to the programming port of the Arduino to connect it to the programming board.
Step 7: Programming
Now, before everything is put together it´s time for some programming and a first function test.
We will use the Arduino IDE and the Adafruit WS2801 Library which can be obtained from GitHub.
For this project I started with the "strandtest" example sketch from the library and edited the data and clock pin lines according to the ones from the previous step, as wells as the number of pixels attached. In this case, each Led counts as a pixel in means of this software.
After all necessary changes are made, compile and upload the sketch to the Arduino using either an FTDI Usb Breakout or any other designated Arduino programming device.
When the upload is finshed connect the power wires to a stable 5V powersupply and you should the Led´s come to life.
Step 8: Assembly
Now there are just a few actions left until the project is finished.
At first drill a hole into the frame to put the power supply wires through, this doesn´t have an exact location, just put it where it fits.
After that, bolt on the bottom panel to the top part, attach the power wires to your supply and put a bottle on your new, self-made, glowing bottle coaster.
Thanks for reading and have some fun while building and hacking this project. If you have any questions regarding this instructable, feel free to send me a message.