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README.md

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+Holiday Lights
+=========
+
+Some twinkling lights for your tree/menorah/office/door/roof/habitrail.
+
+
+Materials
+---------
+
+Uses WS2811 lights, available from Adafruit and fine retailers worldwide.
+
+If you've got more than 100 lights in a string,
+you're probably also going to want an external 5v DC power supply.
+I found a good 10A power supply for about $12 on Amazon.
+You can probably salvage one from some old thing.
+
+If you have under 80 lights, you can use an Adafruit Trinket.
+I used an Adafruit Pro Trinket for mine, which has 150+ lights.
+(It's an issue of RAM).
+
+Of course, a standard Arduino will work just fine too!
+
+
+Setup
+-------
+
+Plug your lights into pin 6 (or whatever you set `PIN` to in the code).
+Set `NUM_LEDS` in the code to how many are in your strip.
+
+Give the strip power and ground.
+If you have more than about 80 LEDs, you might need to provide an external
+5v power supply, since USB can only provide 2 amps. 
+You can plug the LED strip into the +5v on the power supply;
+You can power your microcontroller from the beefier power supply, too,
+so you don't have to run USB just to power the microcontroller.
+
+This was coded to color-correct a specific type of GRB LEDs on wires I got from Amazon.
+It's coded to match the lights we already have, which are biased toward yellow and amber.
+Some of the lights are wired differently and the colors are going to be wrong.
+Play around, commenting out all but one color, to see if it's right.

holiday-lights.ino

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+#include <Adafruit_NeoPixel.h>
+#ifdef __AVR__
+  #include <avr/power.h>
+#endif
+
+#define PIN 6
+#define NUM_LEDS 150
+
+Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, PIN, NEO_GRB | NEO_KHZ800);
+
+const uint32_t colors[] = {
+  0x440000, // Green
+  0x44dd00, // Yellow
+  0x44dd00, // Yellow
+  0x22dd00, // Amber
+  0x22dd00, // Amber
+  0x00ff00, // Red
+  0x008844, // Purple
+  0x000088, // Blue
+};
+
+const int ncolors = sizeof(colors) / sizeof(*colors);
+
+void setup() {
+  strip.begin();
+  strip.show();
+}
+
+void loop() {
+  for (int i = 0; i < 12; i += 1) {
+    int pos = random(NUM_LEDS);
+    if (random(100) < 20) {
+      int color = random(ncolors);
+      strip.setPixelColor(pos, colors[color]);
+    } else {
+      strip.setPixelColor(pos, 0);
+    }
+  }
+  strip.show();
+  delay(240);
+}