Disclosed is a self-construction system of a wireless sensor network, and a method for self-construction of a wireless sensor network using the same. The user can simply plug the multiple function wall cover plate’s prong into the original wall outlet’s receptacle to enable electricity delivery and enjoy the multiple functions of the current invention. Display connection lines are carried by the circuit board and interconnect the display connector and processor for carrying signals from the processor to the display connector and a connected display. The first terminal is connected to the current source transistor through a first impedance element. The time difference between when the frame was sent from the originating switch to when the frame is received back at the originating switch is calculated and designated as the delay value.