Oops, put back rainbow example

Author: PaintYourDragon

examples/rainbow.py

@@ -0,0 +1,57 @@
+# Simple demo of of the WS2801/SPI-like addressable RGB LED lights.
+# Will animate a rainbow color cycle on all pixels.
+# Author: Tony DiCola
+# License: Public Domain
+from __future__ import division
+import time
+
+# Import the WS2801 module.
+import Adafruit_WS2801
+import Adafruit_GPIO.SPI as SPI
+
+# Configure the count of pixels:
+PIXEL_COUNT = 10
+
+# The WS2801 library makes use of the BCM pin numbering scheme. See the README.md for details.
+
+# Specify a software SPI connection for Raspberry Pi on the following pins:
+PIXEL_CLOCK = 18
+PIXEL_DOUT  = 23
+pixels = Adafruit_WS2801.WS2801Pixels(PIXEL_COUNT, clk=PIXEL_CLOCK, do=PIXEL_DOUT)
+
+# Alternatively specify a hardware SPI connection on /dev/spidev0.0:
+#SPI_PORT   = 0
+#SPI_DEVICE = 0
+#pixels = Adafruit_WS2801.WS2801Pixels(PIXEL_COUNT, spi=SPI.SpiDev(SPI_PORT, SPI_DEVICE))
+
+# Clear all the pixels to turn them off.
+pixels.clear()
+pixels.show()  # Make sure to call show() after changing any pixels!
+
+# Define the wheel function to interpolate between different hues.
+def wheel(pos):
+    if pos < 85:
+        return Adafruit_WS2801.RGB_to_color(pos * 3, 255 - pos * 3, 0)
+    elif pos < 170:
+        pos -= 85
+        return Adafruit_WS2801.RGB_to_color(255 - pos * 3, 0, pos * 3)
+    else:
+        pos -= 170
+        return Adafruit_WS2801.RGB_to_color(0, pos * 3, 255 - pos * 3)
+
+# Define rainbow cycle function to do a cycle of all hues.
+def rainbow_cycle(pixels, wait=0):
+    for j in range(256):  # one cycle of all 256 colors in the wheel
+        for i in range(pixels.count()):
+            # tricky math! we use each pixel as a fraction of the full 96-color wheel
+            # (thats the i / strip.numPixels() part)
+            # Then add in j which makes the colors go around per pixel
+            # the % 96 is to make the wheel cycle around
+            pixels.set_pixel(i, wheel(((i * 256 // pixels.count()) + j) % 256) )
+            pixels.show()
+            if wait > 0:
+                time.sleep(wait)
+
+print('Rainbow cycling, press Ctrl-C to quit...')
+while True:
+    rainbow_cycle(pixels)