In the designing of Wireless Sensors Networks, one of the key aspects is the energy consumption of each individual node that composes it.Instead of which kind of energy source would be used in the network deployment, the characterization of the power consumption in each mode of operation should be made for determine the autonomy of each individual node, allowing the appliance of a diversity of techniques and strategies for increasing the entire network reliability.This paper explains the description of a method that allows the measuring of the sensor node current consumption, for the later calculation of the power consumption and energy budget that the node requires for its normal operation.