LogTemp is a small temperature logging project for monitoring sanitary hot water - one temperature sensor is fitted on the in- pipe, and the other is on the back pipe.
The sensors are DS18B20 type 1-Wire attached small things, with 4k7 resistors on the specific legs (this was the hardest part - to figure out the correct wiring, because I'm not an electronic/soldering guy, and I couldn't find a clear correct diagram).
The measurement is made by a FreeTronic EtherTen Arduino-compatible board, by a small program (logtemp.ino) which uses Webduino for the web interface, and DallasTemperatureControl library for the sensor readings.
The logger runs on a remote machine, the logtemp.py cronjob gets the data from the web server on the Arduino, and stores them in RRD. Also creates a graph, too.
I promise I'll create photos about the wiring!