Low Power Current Sensing Node Powered by Harvested Stray Electric Field Energy

Sammanfattning: In this thesis, the possibility of harvesting energy from a multicore power cableconnected to a power outlet is presented and evaluated. By surrounding a powercable with a conductive material connected to ground, it is shown that the dif-ference in potential between the power cable and the conductive material causesa capacitance which can charge a capacitor that in combination with an energymanagement circuit can be used to wirelessly transmit data with an interval de-pending on factors like the length of the surrounding material and the type ofcable it is placed around. In addition to this, a technique to, in a non-invasiveway, sense whether there is alternating current flowing in a multicore power ca-ble is brought up. The results show that this technique can be used to detectalternating current without having a device connected between the power cableand the power outlet. These two sections combined are used to design a surveil-lance system that should monitor consumer electronics in the home environmentwhere there is a fire hazard. The system should send out a warning signal thatis visible for the homeowner to remind the user to switch off the power of theelectronic devices before leaving home.