added neopixel demo

Author: ladyada

M4_Eyes/user_neopixel.cpp

@@ -0,0 +1,34 @@
+#if 0 // Change to 1 to enable this code (must enable ONE user*.cpp only!)
+
+#include <Adafruit_NeoPixel.h>
+
+#define LED_PIN    8
+#define LED_COUNT  4
+Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
+
+void user_setup(void) {
+  strip.begin();           // INITIALIZE NeoPixel strip object (REQUIRED)
+  strip.show();            // Turn OFF all pixels ASAP
+  strip.setBrightness(50); // Set BRIGHTNESS to about 1/5 (max = 255)
+}
+
+long firstPixelHue = 0;
+
+void user_loop(void) {
+  for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...
+    // Offset pixel hue by an amount to make one full revolution of the
+    // color wheel (range of 65536) along the length of the strip
+    // (strip.numPixels() steps):
+    int pixelHue = firstPixelHue + (i * 65536L / strip.numPixels());
+    // strip.ColorHSV() can take 1 or 3 arguments: a hue (0 to 65535) or
+    // optionally add saturation and value (brightness) (each 0 to 255).
+    // Here we're using just the single-argument hue variant. The result
+    // is passed through strip.gamma32() to provide 'truer' colors
+    // before assigning to each pixel:
+    strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(pixelHue)));
+  }
+  strip.show(); // Update strip with new contents
+  firstPixelHue += 256;
+}
+
+#endif // 0