Solar Heating Control
Overview of Christian Schumann's Solarsystem
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/
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
It’s run on a Asus WL500gd with openwrt 0.9.
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.