Battery-less wireless current sensor node utilizing the dependence of charging time of a capacitor on the current flowing through a power line

Abstract

In this paper, we propose and demonstrate a new battery-less wireless current sensor node which transmits data using the power charged in a chip capacitor with a current transformer (CT). Since the charging time depends on the current flowing through a power line, the current value can be known by measuring the transmission interval if the node transmits data every time when the power is charged enough to the transmission. In this node, because analog to digital (AD) conversion is not needed, a simple circuit without a rechargeable battery can be realized.