Clemson's makerspace in the Watt's center has a laser cutter, and I wanted to put it to good use. I thought making a back-lit tiger paw would be cool, but I also wanted to do something with edge-lit acrylic. This project is the combination of both desires.
I'll probably refer to it as WallPaw several times during this Instructable. WallPaw was the code name or project name I gave it, so I had an easy way to keep track of files relating to it.
- 1/4" wood - 2' square
- 3/8" acrylic - 1' by 2'
- WS2812 LED strip - 5 meters
- Arduino Uno
- Arduino Mega
- Infrared receiver module
- 1000 uF capacitors - 5ish
- Connector wire (lots)
- Computer PSU (or 5V and 12V power supply)
- 44-key IR LED remote
- Microphone module - I use MAX9814 or MEMS
- Access to a laser cutter (I used one at Clemson)
- A CNC machine would also work for cutting, but it can't etch acrylic
- Soldering iron
- Third hand necessary
- Hot glue gun (this is essential)
- Wire cutters/strippers
Side note: I buy most of my components on Ebay. I know they aren't reliable or great quality, but for my project I've had good luck with them. I do recommend buying multiples of an item just in case you break one or it doesn't work out of the box, because shipping on Ebay direct from China can take a month or so.
Step 1: Initial Design - Pictures and Vector Files
I downloaded the vector file of the Clemson paw from here, and opened it in Adobe Illustrator to start adding connectors between the toes. I used the pen tool and direct selection tool to draw new connections and delete old ones.
For the acrylic piece I copied each toe one at a time, and resized/centered it until it looked right. Then I drew in a rectangle the right size for my LED to be between the wood and the acrylic
For the pictures of Death Valley and Tillman, I uploaded the picture to this website to create a line drawing of the picture. I messed with settings until it looked right.
Next, I opened the picture in Photoshop. I used the tool in Select --> Color Range to select all the white pixels and delete them. Next I think I increased the contrast and highlights and other things so that the picture was as pure black and white as possible. Lastly, I used the eraser tool to erase stray dots on the picture as much as I could.
For the other two pictures I just had to get them into pure black/white. There are many ways to do this, but I forget exactly how I did it.
You want to save the pictures as .png files then copy paste them into the Illustrator vector file. Make sure the acrylic insert and the wood cutout are the exact same size and include slots for the lights.
IMPORTANT: When you edge-light etched acrylic, it looks a lot better if the etching is on the back side of the acrylic piece. To achieve this, once you center the picture on the part you are cutting out, group them together and mirror horizontally. So in my case I grouped the inner outline of a toe and the picture, and then flipped them horizontally. This should be one of the last things you do so that you don't mess up the size of the wood/acrylic cutout.
Step 2: Laser Cutting
I took my wood and acrylic to the Clemson Makerspace in the Watts Center. Our laser cutter is an Epilog Fusion M2 40 Laser Cutter, it has an engraving area of 40" x 28".
In the vector files I made the outlines have a stroke/thickness of 0.00001" so that the laser cutter software knows to cut those lines all the way through. I used the software default settings for 1/4" wood on the wood pieces. On the acrylic pieces I think we used 100% speed and 2% power to cut the acrylic, and slightly higher than default power for the etching. I left the protective sheet on the back side of the acrylic piece when cutting so that any flames wouldn't scorch the acrylic, just the protective sheet. (Remove the top protective sheet though)
When using a laser cutter, if the software won't do all of your cuts and etches in the same print, just split them up into two separate cuts/files: one file for cutting, the other for etching. Maybe this was just a problem with the Epilog laser, but maybe it's more common.
Step 3: Wiring and LED Installation
Once everything was cut and in front of me, I just used a pencil to trace a path for my LED's and drew where my Arduino boards and power connectors would go. It doesn't need to be precise or have great cable management because it's all on the back of the project where no one will see.
I chose to keep the power supply on the ground instead of on the back of the project to save weight. (Also because I don't have space for a power supply) I used an old computer PSU and just soldered barrel connectors to the 5V and 12V output wires. If you want to use a normal 5V power supply you can plug in the wires to Vin (voltage in) on the Arduino and not have to deal with a boost converter or a secondary supply.
WS2812 LED's are very power hungry - each LED can use up to 60mA, which when multiplied by 200 lights gives us 12A (at 5V = 60 watts). 12 amps is a lot of power, so use some thick wires. I used 10 gauge wire to connect the power supply to the WallPaw, which is probably overkill.
You'll notice I'm using two separate Arduino's for this project. I chose to use two because this tutorial used two, and until I had most of the code written I thought I would need two Arduinos. It turns out that when you write your code correctly, it should work on a single Arduino. You need a Mega if you're doing complicated light arrangements with lots of LED's, because the programming is fairly memory hungry. I used an Uno for a few days, then the code stopped working because it ran low on memory.
All of my light strips are just hot glued to the back of the paw. I tried using foam or something stiffer as a back, but it turned out to not be necessary. Just hot glue them, the LED strips will happily stay in place. FYI hot glue is completely non-conductive, I tested it myself with a multimeter.
The first 198 LED's only took an hour or two to glue and solder, but the acrylic pieces probably took 6 hours total. I didn't make the slot for the LED very wide (so they're inconspicuous), but as a result I had to solder the wires very unconventionally as shown in the picture above. 4 acrylic pieces * 3 LED's each * 6 solders per LED = 72 solders for the LED's alone. Add in the time to measure/cut/strip connecting wires and burn out a few LED's as you solder them and you easily have a 6-8 hour job.
If you're making a version of this, design slots for you LED's much wider than I did. For your own sanity.
Step 4: Programming
I used the FastLED library to control the WS2812 LED's. I used my own LEDCodes library that I made specifically for the 44-key IR remote.
The code generally runs like this
- Arduino 1 (Uno) listens for IR signal
- If it receives a signal, figure out which button on the IR remote it is from
- Send that number (1-44) to Arduino 2 (Mega)
- If it receives a number, change the current mode to that number.
- Check for a new code every 150ms or so
- If the new code is the same as the current code, go to the next sub-mode
The single color buttons on the lights have multiple sub-modes
- All lights on
- Just the acrylic lights and Clemson Tigers
- All lights pulse on/off
- Sound reactive
- Acrylic only
The Red/Green/Blue buttons are set to display two-color combinations of lights
- Outside lights color 1, acrylic+Clemson Tigers lights color 2
- Swap that^
- Alternate acrylic pieces with colors 1 and 2 (so piece 1 and 3 are color 1, piece 2 and 4 are color 2)
- Swap that ^
I copied several cool light modes from this website, such as:
- Scrolling rainbow (my favorite)
- Theater chase
- Snowflake flashing
- Cylon bounce
- Bouncing balls simulation
- Fire simulation
I also made my own functions for sound reactivity using a microphone. You can read them in the MicrophoneFunctions.ino file in the WallpawLightTester.zip file here.
Step 5: Final Product
Feel free to comment or email me questions - I love this stuff and would love to help other people make cool projects. I'm also a hobby/freelance/semi-professional photographer in the Clemson/Greenville SC area, so if you're looking for a photographer contact me!