5. Some simple devices

5.1. Being home

For some scripts it can be important whether I am home. For example: certain lights will go on only when I am there, otherwisw they stat out.

My pressence at home is determined by the fact that my phone is there. My DHCP server hands out a fixed address to the phone, based on the MAC-ID. On th phone, I set the sleep policy to "never":

Settingss
    -> Wireless & Network Setting
        -> Wifi Settings
            -> Press Menu button
                -> Advanced
                    -> WiFi Sleep Policy

That was enough for my Android phone to respond to pings.

I made a virtual hardware device type "Dummy (Does nothing, use for virual switches only)". For that hardware, I made a virtual sensor, type switch. The name of that sensor is assigned to the variable DOMO_DEV in the script below.

The script polls the phone and sets the value of the virtual switch.

 #!/bin/bash
 #REMOTE@ domoticz.home /usr/local/bin/ljthuis
 ##########################################################################
 # Set or change the hostnames below to match your environment
 ##########################################################################
 
 DOMOTICZ='domoticz.home:8888'
 TARGET=192.168.178.219
 DOMO_DEV='laurent-jan_thuis'
 
 ##########################################################################
 helpme(){
 cat <<EOF
 
 NAME: Am i at home?
 
 EOF
 }
 
 if [ "$1" = "-h" ] ; then
     helpme
     exit 0
 fi
 
 verbose=0
 if [ "$1" = "-v" ] ; then
     verbose=1
 fi
 
 debug(){
     if [ "$verbose" = 1 ] ; then
         echo $*
     fi
 }
 
 
 tmp=$(mktemp)
 now=$(date)
 
 # Get list of devices
 curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=devices_list" |
 sed 's/"//g;s/,//' |
 while read nv col val ; do
     if [ "$nv" = 'name' ] ; then
         name="$val"
     elif [ "$nv" = 'value' ] ; then
         echo "$val $name"
     fi
 done > $tmp
 
 
 val=0
 if ping -c5 $TARGET > /tmp/last_ljm.out 2> /tmp/last_ljm.err ; then
     val=1
 fi
 debug "Value: $val"
 idx=$(sed -n "s/ $DOMO_DEV//p" $tmp)
 debug "idx=$idx"
 if [ "idx" = "" ] ; then
     true
 else
     debug curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=udevice&idx=$idx&nvalue=$val" 
     curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=udevice&idx=$idx&nvalue=$val" > /dev/null
 fi
 
 rm -f $tmp

The script runs every 5 minutes from cron

 #USER root@domoticz.home                                                                              #--ljthuis.cron:root
 #INSTALLEDFROM verlaine:src/domoticz                                                                  #--ljthuis.cron:root
 #  m           h  D   M  dow  cmd                                                                     #--ljthuis.cron:root
    1,16,31,46  *  *   *   *   /bin/bash /usr/local/bin/ljthuis > /tmp/last_ljthuis.out 2>/tmp/last_ljthuis.err  #--ljthuis.cron:root
    6,21,36,51  *  *   *   *   /bin/bash /usr/local/bin/ljthuis > /tmp/last_ljthuis.out 2>/tmp/last_ljthuis.err  #--ljthuis.cron:root
    11,26,41,56 *  *   *   *   /bin/bash /usr/local/bin/ljthuis > /tmp/last_ljthuis.out 2>/tmp/last_ljthuis.err  #--ljthuis.cron:root

5.2. Internet connection

I had the impression that my Internet connection was unreliable. To get some data about how unreliable the connection was, I created a custom sensor, with the sensor unit "msec". The value of the sensor is the round-trip time for a ping to 8.8.8.8. Again, an external script updates the value of the sensor.

 #!/bin/bash
 #REMOTE@ domoticz.home /usr/local/bin/internetup
 ##########################################################################
 # Set or change the hostnames below to match your environment
 ##########################################################################
 
 DOMOTICZ='domoticz.home:8888'
 TARGET=8.8.8.8
 
 ##########################################################################
 helpme(){
 cat <<EOF
 
 NAME:
     internetup - test if internet is up
 
 SYNOPSIS:
     p1_report
 
 DESCRIPTION:
 
 Internetup pings $TARGET to see if the Internet is reachable.
 
 The default URL for Domoticz is '$DOMOTICZ' and the default
 target for ping is $TARGET
 
 Internetup is typicaly started by cron to ensure a regular data feed to
 Domoticz.
 
 EOF
 }
 
 if [ "$1" = "-h" ] ; then
     helpme
     exit 0
 fi
 
 verbose=0
 if [ "$1" = "-v" ] ; then
     verbose=1
 fi
 
 debug(){
     if [ "$verbose" = 1 ] ; then
         echo $*
     fi
 }
 
 
 tmp=$(mktemp)
 pingout=$(mktemp)
 now=$(date)
 
 val=500
 if ! ping -c1 8.8.8.8 > $pingout ; then
     sleep 1
     ping -c1 8.8.8.8 > $pingout
 fi
 if grep -q 'time=' $pingout ; then
     val=$(sed -n 's/ ms//; s/.*time=//p' $pingout)
 fi
 debug "Value: $val"
 
 # Get list of devices
 curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=devices_list" |
 sed 's/"//g;s/,//' |
 while read nv col val ; do
     if [ "$nv" = 'name' ] ; then
         name="$val"
     elif [ "$nv" = 'value' ] ; then
         echo "$val $name"
     fi
 done > $tmp
 
 inet_idx=$(sed -n 's/ internet_up//p' $tmp)
 
 debug "inet_idx=$inet_idx"
 
 if [ "inet_idx" = "" ] ; then
     echo "$now No inet dev">> /tmp/last_inet
 else
     debug curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=udevice&idx=$inet_idx&nvalue=1&svalue=$val" 
     curl --silent  "http://$DOMOTICZ/json.htm?type=command&param=udevice&idx=$inet_idx&nvalue=1&svalue=$val" > /dev/null
     echo "$now Internet: $val" >> /tmp/last_inet
 fi
 
 tail -1024 /tmp/last_inet > $tmp
 mv $tmp /tmp/last_inet
 
 rm -f $tmp $pingout

And again, launched from cron:

 #USER root@domoticz.home                                                                              #--internet_up.cron:root
 #INSTALLEDFROM verlaine:src/domoticz                                                                  #--internet_up.cron:root
 #  m           h  D   M  dow  cmd                                                                     #--internet_up.cron:root
    0,15,30,45  *  *   *   *   /bin/bash /usr/local/bin/internetup > /tmp/last_internetup.out 2>/tmp/last_internetup.err  #--internet_up.cron:root
    5,20,35,50  *  *   *   *   /bin/bash /usr/local/bin/internetup > /tmp/last_internetup.out 2>/tmp/last_internetup.err  #--internet_up.cron:root
    10,25,40,55 *  *   *   *   /bin/bash /usr/local/bin/internetup > /tmp/last_internetup.out 2>/tmp/last_internetup.err  #--internet_up.cron:root

The results for my Ziggo line where, that I had a down time of more than 15 minutes about every two days. Also, the tound-trip time varied wildly, between 8msec and 100msec. That jitter was a serious problem in video calls.