gistfile1.txt

import alsaaudio
import serial
#import numpy
import struct
import math

ser = serial.Serial('/dev/ttyUSB0', 19200)

inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NORMAL, 'Device')
inp.setchannels(1)
inp.setrate(1000)
inp.setformat(alsaaudio.PCM_FORMAT_S16_LE)
inp.setperiodsize(120)

def update_lights(rms):
    num = max(min(int(rms*1000.0), 254), 40)
    print num
    ser.write("1c%iw" % num)
    ser.write("2c%iw" % num)
    ser.write("5c%iw" % num)
    ser.write("5c%iw" % abs(100-num))
    ser.write("7c%iw" % num)


def get_rms( block ):
    count = len(block)/2
    format = "%dh"%(count)
    shorts = struct.unpack( format, block )
    sum_squares = 0.0
    for sample in shorts:
        # sample is a signed short in +/- 32768. 
        # normalize it to 1.0
        n = sample * (1.0/32768.0)
        sum_squares += n*n
    print sum_squares
    return math.sqrt( sum_squares / count )


while True:
    l, data = inp.read()
    if (l > 0):
        update_lights(get_rms(data))