Audio recording using element14 Cirus Logic (Raspberry pi) and pyaudio

Hi all,

First of all I should say that I'm quite new to Rasberry Pi and Python. I'm trying to write a Python script which will record audio using the element14 cirus logic board and pyaudio and then apply some signal processing algorithms. What I can't seem to understand is how to specify the Input for my data stream...Here's the code I'm using (for the moment I just want to write the data in a a test file)

import pyaudio

CHUNK = 1024
FORMAT = pyaudio.paFloat32
CHANNELS = 1
RATE = 44100
RECORD_SECONDS = 5
OUTPUT_FILENAME = 'test'

p = pyaudio.PyAudio()

stream = p.open(format=FORMAT,
  channels=CHANNELS,
  rate=RATE,
  input=True,
  frames_per_buffer=CHUNK
  input_device_index = 2)

print("* recording")

frames = []
f = open(OUTPUT_FILENAME,'wb')

runflag = 2
while runflag>0

  data = stream.read(CHUNK)
  f.wite(data)
  time.sleep(.001)
  runflag = runflag-1

print("* done recording")

stream.stop_stream()
stream.close()
p.terminate()

I tried different input_device_index when I open the stream but crashes all the time. However if I use input_device_index=2 it just blocks at stream.read(CHUNK) which I suppose happens because it doesn't get any input data.
Any help would be much appreciated!