Sound activated recording using SOX

sox-vox.sh

#!/bin/bash

tempfile1=/tmp/temp.mp3
# Baremetal/Realtek analog etc
AUDIODEV=hw:0,0
# Pi USB mic (usually):
# AUDIODEV=hw:1,0

set_filenames () {
NAME=`date +%Y-%m-%d_%H-%M-%S`
FILENAME="/tmp/${NAME}.mp3"
#FILENAME="/var/www/Recordings/$NAME.mp3"
}

cleanup_vox () {
[ -f "$tempfile1" ] && rm -rf $tempfile1
}

start_vox () {
cleanup_vox
sox -t alsa -d "$tempfile1" silence 1 0 10% 1 0:00:04 10%
#wait
}

normalize_vox () {
[ -r "$FILENAME" ] && \
sox $FILENAME /tmp/${NAME}-norm.mp3 gain -n -1
}

filesize_vox () {
if [ -r "$tempfile1" ]; then
  for i in "$tempfile1" ; do
    b=`stat -c %s "$i"`
    if [ $b -ge 390 ] ; then
      set_filenames
      cp "$tempfile1" "$FILENAME"
      normalize_vox
      break
    fi
  done
fi
}

# Execute functions in infinite loop
while :
  do
    start_vox && \
    sleep 1        # so you can exit loop easily w/ ctrl-c
    filesize_vox && \
    cleanup_vox && \
    echo
    sleep 1        # so you can exit loop with ctrl-c
  done

exit 0