Fhem is a GPL’d perl server for house automation. It is used to automate some common tasks in the household like switching lamps / shutters / heating / etc. and to log events like temperature / humidity / power consumption.
The program runs as a server, you can control it via web or smartphone frontends, telnet or TCP/IP directly.
In order to use fhem you’ll need a 24/7 server (Fritz!Box, NAS, RPi, PC, MacMini, etc) with a perl interpreter and some attached hardware like the CUL, FHZ1300PC, etc. to access the actors and sensors. See the «Supported hardware» section below.