#!/usr/bin/env python3
import pyaudio
import numpy as np
CHUNK = 2*4096 # number of data points to read at a time
RATE = 48000 # time resolution of the recording device (Hz)
DEVICE = 1 # Webcam
p = pyaudio.PyAudio()
stream=p.open(format=pyaudio.paInt16,channels=1,rate=RATE,input=True, input_device_index=DEVICE,
frames_per_buffer=CHUNK)
while True:
indata = np.fromstring(stream.read(CHUNK),dtype=np.int16)
# Take the fft and square each value
fftData=abs(np.fft.rfft(indata))**2
# find the maximum
which = fftData[1:].argmax() + 1
# use quadratic interpolation around the max
if which != len(fftData)-1:
y0,y1,y2 = np.log(fftData[which-1:which+2:])
x1 = (y2 - y0) * .5 / (2 * y1 - y2 - y0)
# find the frequency and output it
thefreq = (which+x1)*RATE/CHUNK
print("The freq is %f Hz." % (thefreq))
else:
thefreq = which*RATE/CHUNK
print("The freq is %f Hz." % (thefreq))
stream.close()
p.terminate()