SDS011 Sensor auslesen

#!/bin/bash

WDIR=.

stty -F /dev/ttyUSB0 9600 raw

INPUT=$(od --endian=big -x -N10 < /dev/ttyUSB0|head -n 1|cut -f2-10 -d" ");

#Ausgabe
echo $INPUT
echo " "

FIRST4BYTES=$(echo $INPUT|cut -b1-4);
echo $FIRST4BYTES

if [ "$FIRST4BYTES" = "aac0" ]; then
  echo "check for correct intro characters: ok"
  logger "check for correct intro characters: ok"
else
  echo "incorrect sequence, exiting"
  logger "incorrect sequence, exiting"
  exit;
fi

PPM25LOW=$(echo $INPUT|cut -f2 -d " "|cut -b1-2);
PPM25HIGH=$(echo $INPUT|cut -f2 -d " "|cut -b3-4);

PPM10LOW=$(echo $INPUT|cut -f3 -d " "|cut -b1-2);
PPM10HIGH=$(echo $INPUT|cut -f3 -d " "|cut -b3-4);

#zu Dezimal konvertieren
PPM25LOWDEC=$( echo $((0x$PPM25LOW)) );
PPM25HIGHDEC=$( echo $((0x$PPM25HIGH)) );

PPM10LOWDEC=$( echo $((0x$PPM10LOW)) );
PPM10HIGHDEC=$( echo $((0x$PPM10HIGH)) );

PPM25=$(echo "scale=1;((( $PPM25HIGHDEC * 256 ) + $PPM25LOWDEC ) / 10 ) "|bc -l );
PPM10=$(echo "scale=1;((( $PPM10HIGHDEC * 256 ) + $PPM10LOWDEC ) / 10 ) "|bc -l );

logger "Feinstaub PPM25: $PPM25"
logger "Feinstaub PPM10: $PPM10"

echo "Feinstaub PPM25: $PPM25"
echo "Feinstaub PPM10: $PPM10"

echo $PPM25 >> $WDIR/etc/ppm25.txt
echo $PPM10 >> $WDIR/etc/ppm10.txt

# wget "http://data.sparkfun.com/input/[publicKey]?private_key=[privateKey]&pm10=[value]&pm25=[value]"