Introduction: NeoPixel Pie Tin Arduino Wreath
Provided here are instructions for making a newfangled version of my Pie Tin Holiday Wreath Instructable.
Instead of store-bought GE lights, the pie tins are now illuminated with DIY holiday lights homemade with "NeoPixels". NeoPixels are user-programmable, color changing LED's. The light show is custom programmed using Arduino code, which is loaded onto an Arduino UNO or compatible CPU chip. The resulting decoration is stand alone (battery powered) and light weight. Shareware software, for example Adafruit.com's Arduino library, makes programming of a custom light show relatively easy for those so inclined.
Please don't let the Christmas holiday motif fool you. What we really have here is a scaled-up 4-ft diameter version of Adafruit's 1.5-inch diameter 12xNeoPixel ring, with many decorative possibilities.
4 x Poster Board Sheets (Pacon Water-Resistant Foam Board 20x30-in)
12 x NeoPixel LED's (WS2812B Addressable 5050 RGB SMD on PCB Board)
12 x LED Light Diffusers (Clear empty bulbs)
Arduino Uno Board
Small Arduino compatible board (SparkFun.com LilyTiny ATTiny85 board)
Decorative Red Lighted Bow Ornament (Walmart)
3.7v Lithium Battery (or 4 x AA alkaline battery with holder)
Wire and Solder Supplies
Duct Tape and other craft accessories
(See also my prior Instructables for the pie tin Christmas Tree, Hanukah Menorah, Great Pumpkin, Holiday Wreath, New Years Time Ball)
Step 1: Obtain or Make Clear Diffuser Bulbs (12)
The basic concept of this project is to make your own colorful Xmas light bulbs.
To accomplish this, clear bulb covers (light diffusers) and pie tins will be attached onto the front side of a foam board with holes for inserting the base of the bulbs. The bulbs will then be illuminated from behind with the NeoPixel LEDs.
There are 3 basic ways to obtain the clear bulbs (diffusers)- they can be purchased, or made with a 3D printer, or scavenged from a commercial light string.
For today's project I am scavenging 12 clear bulbs from an older GE Color Effects light string. These are big G35-size clear plastic (hollow) bulbs, with a 13/16-inch base. The base of the clear bulb inserts snuggly into a 13/16-hole cut in poster board.
Step 2: Make the Circular Backing Board
I used Pacon Water Resistant Foam Board, and cut out a giant circle with a 35-inch central diameter for spacing 12x9-in pie tins at approximate 9.1-inch spacing. Because each sheet of foam board is only 20x30-inch, I made the backing board in 4 pieces, and taped them together with duct tape as shown.
An X-Acto knife can be used or cutting the 13/16-inch holes for inserting the bulb diffusers. However, I used a Lion Ev-R-Round Perfect Circle Cutter to make clean holes in the poster board. Because the Lion circle cutter only cuts to 1/4-inch depth, two passes (one cut on top of the foam board, and one below) are required to make the holes.
I painted the backing board green with acrylic craft paint. However it was hard to get good paint adhesion onto the special water-resistant poster board. This painting step is not critical and can skipped. The backing board is not visible at night, so I was mainly trying impart further water proofing.
Step 3: NeoPixel LED Options
For this project I decided to try the following NeoPixels: ALITOVE's WS2812B Addressable LED Pixel Light 5050 RGB SMD on Heat Sink PCB Board 5V DC Compatible with Arduino, Raspberry Pi, available from Amazon for $16 for 100 pieces. That's only 16-cents per NeoPixel.
See enlarged picture above for these NeoPixels. This project uses 12 NeoPixel LEDs. Each LED chip features two Positive (+5V) solder pads, two Ground or Negative (gnd -) solder pads, one Data In (Din) solder pad and finally one Data Out (Dout) solder pad. All six solder pads must be used to connect the 12 NeoPixel LED's in series. The "data" refers to the light show digital instructions coming into the light string from the Arduino or other compatible memory chip, which is passed into LED1, and then from LED1 out to LED2...finally down the string to LED12.
NeoPixels are also available for purchase from Adafruit.com. Some folks may find the Adafruit Flora NeoPixels Ver2 easier to work with, because that style features through-the-hole soldering connections.
Step 4: Wiring the NeoPixels
The NeoPixels are soldered together in a 12-LED light string, as shown in the wiring diagram and photos above. About 10-inches of wire between each NeoPixel LED allows enough slack in this project. Note that, to prevent burnout of the NeoPixels, I normally insert a 480 Ohm resistor on the data line input ahead of the first NeoPixel LED (as shown in the wiring diagram).
As for hook-up wiring, I like to use Radio Shack 24AWG 4-conductor solid intercom wire, which can be easily trimmed down to 3-wires. However, that wire may no longer be available for purchase. .
Duct tape is used to secure the light string to the backing board, and to orient the NeoPixels to shine out through the bulbs.
At the bottom of the wreath, a small wooden board (from the Walmart-craft department) is attached to the back to mount the battery and small LilyTiny (ATTINY85) PCBoard as shown.
NOTE: Please disregard the fact that wiring insulation colors I used in my completed project do not match the wiring colors in the wiring diagram. Simply put, its is hard to find 3-conductor wire in the exact color scheme you might want for the NeoPixel LEDs.
Step 5: Prepare Pie Tins
The Hefty or Reynolds E-Z Foil Pie Pans for 9-inch recipes look great as reflectors. These 9-inch pie tins are the ones with the 8-point "star" shape in the middle. However, the E-Z Foil brand has been hard to find in 2020, so other similar 9-inch pie tins can be substituted. The E-Z Foil 9-inch pie tins are actually 8-3/4 inch inner diameter (inside the rim), which allows spacing them about 9.1-inches apart in this project. Using an X-Acto knife or equivalent, cut a 3/4-inch diameter hole in the center of each pie tin. For this project I used a Jefferson nickel coin as guide for cutting the center hole. A total of 12x9-inch pie tins are used in the circular pattern.
Step 6: Insert Bulbs/Pie Tins and Hanging Hardware
The bulbs and pie tins are then inserted in to the holes in the poster board. I put a little double-sided Scotch tape around the base of the bulbs to help hold them in more snuggly.
Under the top tab of the wreath, a small wooden board (from the Walmart-craft department) is attached to mount hanging hardware.
A decorative red lighted bow (Walmart) is used to adorn the wreath.
Right now I am keeping the wreath out of the rain. Bullet proofing the design for all weather is a future action item.
Step 7: Programming the Light Show
If you are not familiar with NeoPixel LED's and Arduino's, but would like to learn, Adafruit.com's NeoPixel tutorials are a good place to start.
For this project I am simply using Adafruit.com's "STRANDTEST" light show code from the the Adafruit NeoPixel program library for Arduino. I made a few simple edits to the STRANDTEST code, for example I added a DELAY hold step after the wreath turned Christmas green. Additionally, I observed several of the color chases were moving too fast, given the huge 4-ft diameter of the pie tin wreath, so I slowed down several of the chase sequences.
YouTube LINK for Video of Wreath Display: https://youtu.be/qcu_U-GFcQQ
Normally I start out loading the Arduino code (eg; the modified STRANDTEST 12) into a full size Arduino Uno board for trial runs. When satisfied, I load the Arduino code into a smaller chip. Historically I like to use the SparkFun.com LilyTiny ATTiny85 in my final projects, which tends to be a little trickier to program (see instructions at SparkFun.com). The Adafruit equivalent small chip, probably more convenient to program via common USB connection, would be their Gemma and/or Trinket boards, which I intend to use more in the future.
Aside from Adafruit.com's NeoPixel software library, FastLED apparently provides another 3rd party source of light show software.
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