There and Back Again

I decided it was time for me to create a wall hanger that showcased one of my many favorite book/movie series to hang on my form room wall. I chose to etch a map of Middle Earth using a laser cutter, and to add some neopixel backlighting . For this project you will need the following tools and materials:

Tools:

- Laser cutter

- Sandpaper, handheld sander optional

- Hot glue gun

- Soldering Iron

- Cable to connect laptop and Arduino

-Laptop with Arduino IDE installed

Materials:

- 1/4 inch thick plywood sheet, can be sourced from Home Depot

- Hot glue sticks

- Solder

- Flux

- Arduino board (I used R3 Uno)

- Jumper wires

- 2 meters 60/meter neopixel strand

- Tape (I ended up using both duck-tape and masking tape)

- Heatshrink for soldered connections

- Fishing line

First I found the biggest map of Middle-Earth I could find online that was high quality(see attached image, found at https://musicoftheainur.wordpress.com/2013/06/08/4... ). Then I began testing the raster etching process by using a scrap piece of 1/4" plywood to test the laser cutter settings for speed and power.

I ended up having to use a dithered image of the map that I created in the laser cutter software. I used a resolution of 1000, with a frequency of 60 lines per inch for my final etching. I settled on final dimensions of 19.35 inches by 18.17 inches.

After making 6 test etchings varying both the speed and power of the laser I found that 13.5 min and max power, and 100 speed produced an image that I was happy with. Then I loaded in my plywood sheet and etched the full map, which took about 4 hours give or take 15 minutes. Once it was etched I cut down my wood sheet, giving about a 1.5 inch border around the edges of the map.

I wanted the backlighting to have an animated fire-like effect as I feel that a fire effect fits the Lord of the Rings theme. Since I have little experience with arduino and neopixels, I started by googling for examples of this effect. I found one that I liked here: http://www.walltech.cc/neopixel-fire-effect/

I then modified the example code to fit my 2 meter strand ( which I ended up shortening by 24 neopixels when i attached the neopixels to the back of the plywood).

I wired up the strand to my arduino board using VIN for power, ground, and pin 6 for digital. Upon initial upload the LEDs were much to bright, you could barely tell that they were supposed to be fire orange, but when I tried to change their brightness, i couldn't connect to the arduino board. After consulting more experienced arduino users, I figured out that my laptop wasn't providing enough power for all the lights and the arduino itself, so while I was making changes to the code I used an external 5V power supply.

Once I was able to make changes I decreased the brightness of the strand and started playing around with the shades of orange and yellow. I also played around with the delay time, which affects how fast or slow the "flames" flicker.

Once I had the lighting done, I needed to create a frame to mount the neopixels to, and reduce the warping in my etched piece of wood. I used some scrap half inch thick MDF board that I had from a previous project. I cut the MDF into 4 strips to glue to the back of the map piece. I eyeballed a length that would give me about a 2-3 inch overhang on the map side, and glued the strips down. To make sure that they are all fit I used the first horizontal and vertical strip to cut the second of each respectively.

After gluing I flipped the map board over sot eh map side was face up and used whatever I had on hand to weight down the plywood to ensure that it would stay glued to the MDF frame. Once the glue was set I removed the weight and flipped the panel over to expose the framing. Then I cut a piece of fishing line (2 ish feet long) and used hot glue to attach it to the top corners of the frame. The fishing line is used to hang the finished piece, so make sure it is securely attached. The fishing line ended up, when hanging, being just about even with the top edge of the plywood.

The frame was just thick enough that the arduino and wires could be tucked inside the frame without any issues. So, I used ducktape to create a pocket for the arduino board to sit in and a second pocket for an external battery pack that can be used to power the lights through the board to minimize visible wires. A 5V power adapter, the kind that may phones use to charge could be substituted for the battery pack, but you may need to use a longer cable to connect to the arduino, which most likely will be visible below the hanging.

After leaving it hanging for a while I did notice that the VIN socket can become hot. To alleviate this, the neopixel strand will need to have supplemental power supplied to it. A 5V power supply can be stepped down and/or adapted so it can supply power directly to the neopixel strand, and I plan to add this in soon.