Patent ID: 8878689

Claim:
A meter reader for reading a meter having a display portion displaying a total output of a quantity being metered and plural incremental outputs defining the total output, comprising: an infrared (IR) light illuminating device configured to illuminate the display portion; a sensing device having a plurality of sensors and configured to optically sense only one incremental output of the plural incremental outputs defining the total output in the meter display portion, including a differential decoder configured to compare respective signals, obtained from at least one pair of spatially separated sensors of the plurality of sensors, with each other and to generate incremental outputs based on the comparing, the sensing device being disposed over the only one incremental output; a processing unit coupled to the sensing device and configured to accumulate said incremental outputs sensed by the sensing device and to determine accumulated meter output over a time period based on the accumulated incremental outputs; an output device configured to output the accumulated meter output determined by the processing unit; and a power management device configured to disable the infrared illuminating device and the sensing device after incremental outputs for periods of time determined based on the rate of change of the quantity being metered, wherein the only one incremental output corresponds to a least significant incremental output of the plural incremental outputs defining the total output, wherein the plurality of sensors are configured to sense only the least significant incremental output in usage included in the meter display portion, and wherein the infrared illuminating device is configured to directly illuminate only the least significant incremental output included in the meter display portion.