NewScientistTech has an intriguing article about research into using electrical noise (noise made by household appliances as they are switched on and off) instead of cameras, microphones, or sensors to automate smart homes.

The new method relies on a device plugged into a single standard wall socket that monitors noise in the electrical supply caused by electrical devices being switched on and off. A computer monitoring the device can then infer that a person must be in that location.

Read the article here.