Systems and methods for sensing environmental changes using electromagnetic interference (EMI) signals are disclosed herein. An EMI monitoring system may be used to monitor an EMI signal of one or more light sources provided over a power line, e.g., in a home or building. The received EMI energy at the power line may be analyzed to detect variations in the EMI signature indicative of environmental changes occurring in the proximity of the light sources. Environmental changes that may be sensed include, but are not limited to, proximity, touch, motion, and temperature change.