leds.py

#!/usr/bin/env python

import spidev
import time

speed = 1000000
bpw = 8

spi = spidev.SpiDev()
spi.open(0,0)
spi.bits_per_word = bpw
spi.lsbfirst = False
spi.mode = 0
spi.max_speed_hz = speed

count=100

r=0
g=96
b=192

def f(v):
        l = v % 256
        o = int(v / 256)%2
        if o == 0: return l
        return 255-l
        
while True:
        p = []
        for i in range(count):
                p.append(f(r+i))
                p.append(f(g+i))
                p.append(f(b+i))
        spi.xfer2(p, speed, 500, bpw)

        r += 9
        g += 5
        b += 3

        time.sleep(0.01)