Solar Heating Control
Overview of Christian Schumann's Solarsystem
Design
I have helped Christian Schumann with scripts to control his Solar-panel + rainwater buffer with switches and water-pump.
There are several cronjobs which run every minute, and one of the scripts frequently return “Data error” when reading a DS2890. Reading the sensor second time works almost every time.
Christian Schumann created a quick overview of the system, and I added the temperature’s and sensors in the picture with imagemagick.
Take a look at: http://home.mag.cx/sommer/
Code
My scripts looks like this when reading the data:
#!/bin/ash
readsensor () (
VAL=`owread -s 3002 $1/$2 2>&1`
ERR=$?
[ $ERR != 0 ] &&
}
# save last value to a file as well (mostly for web-server)
[ "$2" = "temperature" ] && echo "$VAL" > /tmp/last_val.$1.$2
echo "$VAL"
true;
)
writesensor () (
VAL=`owwrite -s 3002 $1/$2 $3 2>&1`
ERR=$?
[ $ERR != 0 ] &&
}
true;
)
VAL=`readsensor $SENSOR PIO`
ERR=$?
[ $ERR != 0 ] && exit 1
Platform
It’s run on a Asus WL500gd with openwrt 0.9.
Extensions
I have made a simple web-interface to control some switches and potentiometers via cgi-scripts too, but it’s still a major hack and under development.
Perhaps I can show it in a few days. I don’t want to give out the URL to Christian Schumann’s web-interface even if it’s password protected.
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