Building smart homes requires technology for monitoring activities which is accurate, and cheap. Monitoring a living environment through audio only is cheap, non-invasive and if we use wireless devices with a long lifetime such as sensor network nodes or motes, then it can also be easy to retro-fit in an existing home. Here we report our work on detecting events that occur in a domestic living environment using an audio source alone. Using data from only one microphone in an actual home we show how root mean square (RMS) of volume, which is cheap to compute, can detect most events though eliminating cross-talk from outside noise remains an issue to be overcome. We also outline how we are building cheap, wireless, power-efficient sensor nodes to realise the home monitoring described here.