This post from Karl Lattimer shows how to use RTL-SDR to gather readings from a home energy monitor via the rtl_433 written by Benjamin Larsson aka merbanan. The rtl_433 is a very interesting package which will not only allow you to sniff communications of several wireless home devices but it will also decode the protocol of many of those rendering things extremely easy in some cases. Just read through this link to see just how many things you might have at home that could already be hacked into.
The tutorial from Karl is specific for the OWL CM160 which I was interested in as I own one as well. I haven’t yet managed to make things working but it doesn’t mean that this is not worth sharing already, isn’t it?
Many cheap USB TV Tuners are based on the RTL chip
so get yourself one of these Tuners, install the rtl_433 on your Raspberry Pi and start owning the wireless signals in your house.