use inotifywait

scripts/spectrogram.sh

@@ -12,18 +12,13 @@ if [ "$LOGGING_LEVEL" == "info" ] || [ "$LOGGING_LEVEL" == "debug" ];then
   set -x
 fi
 
-# Time to sleep between generating spectrogram's, default set the recording length
-# To try catch the spectrogram as soon as possible run at a smaller intervals
-SLEEP_DELAY=$((RECORDING_LENGTH / 4))
+# Continuously loop generating a spectrogram
+inotifywait -m -e close_write "$HOME/BirdNET-Pi/analyzing_now.txt" |
+while read; do
+  analyzing_now="$(<$HOME/BirdNET-Pi/analyzing_now.txt)"
 
-# Continuously loop generating a spectrogram every 10 seconds
-while true; do
-  analyzing_now="$(cat $HOME/BirdNET-Pi/analyzing_now.txt)"
-
-  if [ ! -z "${analyzing_now}" ] && [ -f "${analyzing_now}" ]; then
+  if [ -n "${analyzing_now}" ] && [ -f "${analyzing_now}" ]; then
     spectrogram_png=${EXTRACTED}/spectrogram.png
     sox -V1 "${analyzing_now}" -n remix 1 rate 24k spectrogram -c "${analyzing_now//$HOME\//}" -o "${spectrogram_png}"
   fi
-
-  sleep $SLEEP_DELAY
 done