camera_audio_trigger.py

camera_audio_trigger.py

#!/usr/bin/python

import alsaaudio, time, audioop
import sys
import piggyphoto


# init camera
try:
    C = piggyphoto.camera()
    print "Found the following camera:"
    print C.abilities
except piggyphoto.libgphoto2error:
    print "Found no camera"
    sys.exit(1)

inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE,alsaaudio.PCM_NONBLOCK)
inp.setchannels(1)
inp.setrate(8000)
inp.setformat(alsaaudio.PCM_FORMAT_S16_LE)

inp.setperiodsize(160)


loudness_threshold = 1000

# wait at least for one second before triggering the
#next photo
after_photo_timeout = 1.0

t_last_photo = 0


print "waiting for sounds - the camera reaction might"
print "be a bit slow on the first shot"

while True:
    # Read data from device
    l,data = inp.read()
    if l:
        # Return the maximum of the absolute value of all samples in a fragment.
        try:
            max_v = audioop.max(data, 2)
            if max_v > loudness_threshold:
                c_time = time.time()

                if (c_time - t_last_photo) > after_photo_timeout:
                    print "\nTaking photo (sound level @ %d)" % max_v

                    C.capture_image('snap_%s.jpg' % str(c_time))
                    t_last_photo = time.time()
                else:
                    sys.stdout.write(".")
                    print max_v
        except audioop.error, e:
            if e.message != "not a whole number of frames":
                raise e

    time.sleep(.0001)