= Raspberry Pi and DS18S20 temperature measurement = This page records some work on using DS18S20 with Raspberry Pi and plotting using AWK, SVG and JavaScript. == Raspberry Pi and DS18S20 == One wire - DS18S20 reader Used GPIO4 pin 7 - middle pin. 3v3 to power gnd to gnd / 3v3 ----------------+ DS18S20 - top (|- buss --GPIO4--[4k7]--/ \ gnd Web pages to help:- http://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/hardware http://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/hardware http://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/ds18b20 == Shell Script - loop.sh == The script below puts the

#! /bin/bash
#	
#  Shell Script to poll temperature chips 
#  usage:	 bash loop.sh
#
# http://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/hardware
#
echo "---------------------"
ls /sys/bus
echo "---------------------"
sudo modprobe w1-gpio
sudo modprobe w1-therm

echo "---------------------"
ls /sys/bus
echo "---------------------"

while [[ 1 ]]
do
  echo "========" 		    > ~/Desktop/tmp.txt
  date 				   >> ~/Desktop/tmp.txt
  cat /sys/bus/w1/devices/10-*/name >> ~/Desktop/tmp.txt
  cat /sys/bus/w1/devices/10-*/w1* >> ~/Desktop/tmp.txt
  echo " "			   >> ~/Desktop/tmp.txt
  #
  # use AWK to extract the temperatures. appends gbF() to gbookFtemp.js
  #
  cat ~/Desktop/tmp.txt
  awk -f loop.awk ~/Desktop/tmp.txt 

  cat ~/Desktop/tmp.txt >> ~/Desktop/loop_log.txt
  sleep 3 
  
done  

== Awk Script loop.sh ==

This awk script extracts the temperature and puts the results into a javascript include file.

#
#
# loop.awk
#
# usage: 	awk -f loop.awk loop_log.txt
#
#
# pull out the temperature from loop_log.txt written by loop.sh
# Appends to "gbookFtemp.js"
#
#
#//gbF( name,email,postedOn,IPaddress,userfield1,userfield2,userfield3,userfield4,comments){


BEGIN {
  FS="="

  # zero the temperatures
  ln[1]=0
  ln[2]=0
  ln[3]=0
  ln[4]=0
  # print "" > "gbookFtemp.js"
  notFirst = 0
}

/====/{
  print $0
  getline
  print $0
  
  lnp=1
  cnt +=1
  if ( notFirst ){
    print "gbF( 'awk','t@pi','" lastDate " ','127.0.0.1'," ln[1] "," ln[2] "," ln[3] "," ln[4] ",'comments');" >> "gbookFtemp.js"
  }
  # prepare for next readings
  notFirst = 1
  ln[1]=0
  ln[2]=0
  ln[3]=0
  ln[4]=0
  lastDate = $0
}

/t=/{
  # found a line with a temperature
  ln[lnp] = ($NF/1000) 
  lnp ++
}

END {
  cnt +=1
  print "gbF( 'awk','t@pi','" lastDate " ','127.0.0.1'," ln[1] "," ln[2] "," ln[3] "," ln[4] ",'comments');" >> "gbookFtemp.js"
}



== SVG - loopDS18S20reportSVG.svg ==
The SVG below includes the readings in gbookFtemp.js and plots them.