I got a small "heating" subproject up and running.
See for yourself http://www.knopfdruck.net/projekte/linuxwetter/ (click on the two graphs FHT, today I measure only the room-temperature and the valve setting, more values in the future).
The FHT (and FHZ) is a radio controlled thermostat system (e.g. http://shop.elv.de/output/controller.as ... ail2=10295 sorry for the german link only). There are other actors and sensors available too, which I don't use (yet
).The FHZ-projekt has its own forum and pages: http://www.koeniglich.de/fhz1000/fhz1000.html and http://groups.google.com/group/FHZ1000-users-on-unix
What I did to visualize it with cacti and rrd:
* I remotly insert the values of these thermostates in a mysql-db on my cacti-server.
* Then I update the rrd-file via cronjob with the newest values from the mysql-db.
* Cacti does the graphing.
Greetz,
Sven