The Dylos air quality monitor with serial to USB port was connected to the raspberry pi. Raspberry pi connected through mini USB for power, LAN is connected to RPi, for SD card preparation followed this

• using DD already had a .img file of old raspberry pi SD card Linux files
• make fresh SD card for RPi, SD card is formatted with FAT file formate and then run
• df -h to view the currently mounted devices
• it shows the presence of “/dev/mmcblk0p1”
• then unmounted the /dev/mmcblk0p1
• then ran this command dd bs=4M if=~/2012-12-16-wheezy-raspbian.img of=/dev/mmcblk0
• it took several hours to perform
• then remove cache by sudo sync and safely removed the card
• Now the raspberry pi is working from the SD card based on http://elinux.org/RPi_Easy_SD_Card_Setup
• Steps for viewing the attached serial to USB devices in case of DYLOS air quality monitor /dev dmesg | grep -i tty based on http://www.linfo.org/dmesg.html
• Now to use this for data logging and GSM data transmission for data logging python script from this replay #3 http://forum.arduino.cc/index.php?topic=105148.0 was used

import serial
import time
ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=60)
time.sleep(60)
logfile = open('test.csv', 'a')
while 1:
        line = ser.readline()
        now = time.strftime("%Y-%m-%dT%H:%M:%S:00.000000+0530", time.localtime())
        a =  "%s,%s" % (now,line)
        print a
        logfile.write(a)
        logfile.flush()
logfile.close()
ser.close()

• To make the RPi run automatically this script for every reboot, followed this well written tutorial http://blog.scphillips.com/2013/07/getting-a-python-script-to-run-in-the-background-as-a-service-on-boot/ the steps were:
• added this line to the first line of python script #!/usr/bin/env python
• then moved this file to the location of /usr/local/bin/myservice here myservice folder has to be created
• Execute the command for the file chmod 755 pythonscript.py
• then create a file in /etc/init.d as pythonscript.sh

• add following codes in it

   #!/bin/sh
   ### BEGIN INIT INFO
   # Provides: myservice
   # Required-Start: $remote_fs $syslog
   # Required-Stop: $remote_fs $syslog
   # Default-Start: 2 3 4 5
   # Default-Stop: 0 1 6
   # Short-Description: Put a short description of the service here
   # Description: Put a long description of the service here
   ### END INIT INFO
   # Change the next 3 lines to suit where you install your script and what you want to call it
  DIR=/usr/local/bin/myservice
  DAEMON=$DIR/pythonscript.py
  DAEMON_NAME=pythonscript
  # This next line determines what user the script runs as.
  # Root generally not recommended but necessary if you are using the Raspberry Pi GPIO from Python.
  DAEMON_USER=root
  # The process ID of the script when it runs is stored here:
  PIDFILE=/var/run/$DAEMON_NAME.pid
  . /lib/lsb/init-functions
  
  do_start () {
  log_daemon_msg "Starting system $DAEMON_NAME daemon"
  start-stop-daemon --start --background --pidfile $PIDFILE --make-pidfile --user $DAEMON_USER --startas $DAEMON
  log_end_msg $?
  }
  do_stop () {
  log_daemon_msg "Stopping system $DAEMON_NAME daemon"
  start-stop-daemon --stop --pidfile $PIDFILE --retry 10
  log_end_msg $?
  }
  
  case "$1" in
  
  start|stop)
  do_${1}
  ;;
  
  restart|reload|force-reload)
  do_stop
  do_start
  ;;
  
  status)
  status_of_proc "$DAEMON_NAME" "$DAEMON" && exit 0 || exit $?
  ;;
  *)
  echo "Usage: /etc/init.d/$DEAMON_NAME {start|stop|restart|status}"
  exit 1
  ;;
  
  esac
  exit 0
  

• Execute command for this file chmod 755 pythonscript.sh

• now test it with this command sudo /etc/init.d/pythonscript start it will show [ok ] Starting system dylos_csv_ser daemon:.

• now give this command sudo /etc/init.d/dylos_csv_ser.sh stop

• it give this error

  [….] Stopping system dylos_csv_ser daemon:start-stop-daemon: warning: failed to kill 2794: No such process No process in pidfile ‘/var/run/dylos_csv_ser.pid’ found running; none killed.
  

• Check any pesky mistake in the python script.

• cd into the python script directory then run ./pythonscript.py it has to run without error otherwise the problem is in the python script, mine was due to a space in front of the python (Hrrrrrrah) interpreter in the python script #!/usr/bin/env python after changing this, all are fine

• Another tip to rename files in Linux mv file1 file2 have to catious it will replace the file, can see more option in http://www.cyberciti.biz/faq/linux-rename-file/

• that is it, a python script is in daemon and keeps automatically work after rebooting.

• For GSM-based transmission of DYLOS reading, use http://misc.flogisoft.com/phone/gammu_send_sms