Low power sensor communication using two or fewer wires

Abstract

A device includes a first control element which transitions a sensor module between an active and an inactive mode. A second control element is configured to adjust currents drawn by the sensor module during the inactive mode—such currents corresponding to sensor readings. A processor is coupled by a power signal to a sensor module, which operates over an active sensor, a transition, and a data transfer state. Currents drawn during the active sensor state are substantially constant. During transition, currents decrease from the substantially constant current to a minimum current. During data transfer, currents vary between the substantially constant current and the minimum current. A logical element is configured to monitor the current drawn by the sensor module and, based on variations therein, determine the operating state of the sensor module. A method for using the processor is also disclosed.