A low-cost Wi-Fi smart plug with on-off and Energy Metering functions

This paper presents development of a Wi-Fi smart plug which is able to switch on/off remotely electrical appliances connected. It also monitors their energy consumption. A web application is developed so that users may interface with the smart plug. A bi-stable (latching) relay is employed in the single phase in order to reach zero consumption of the relay coil when it is stable. Measurement accuracy is compared between the proposed smart plug and PSR 1.3 reference meter. The results suggest that error is less than 0.5%.