Microwave Radar Implementation in Outdoor Home Alarm Systems

Abstract: The use of short range microwave radars for motion sensing purposes are on the rise in multiple industries, as they are accurate, small in size and relatively cheap. The automotive industry, in particular, has pushed the development forward. Lately, the home alarm industry has also been glancing at the technology. Radars are well suited for outdoor applications as they are insensitive to precipitation, fog and hot weather that has an impact on the performance of the more common sensors used for intrusion detection: cameras and passive infrared (PIR) sensors. This report investigates how a microwave radar can be implemented as a motion sensing detector in a battery powered outdoor alarm device. Two microwave radars are evaluated before one is chosen for further testing. The experiments are conducted with a focus on the performance of the radar compared to the PIR, as well as the radar’s adequacy in an outdoor environment. The final result is a prototype containing a PIR sensor and a camera together with a 24 GHz radar as a secondary sensor. Even though the radar outperforms the PIR, it is too power consuming to be implemented as the primary sensor of a battery driven device. The report concludes that low cost, low power radar sensor may very well be a part of the next generation home alarms.