In this paper, we study the problem of maintaining sensing coverage by keeping a small number of active sensor nodes and a small amount of energy consumption in wireless sensor networks. This paper extends a result from [21] where only uniform sensing range among all sensors is used. We adopt an approach that allows non-uniform sensing ranges for different sensors. As opposed to the uniform sensing range node scheduling model in [21], two new energy-efficient models of different sensing ranges are proposed. Our objective is to minimize the overlapped sensing area of sensor nodes, thus to reduce the overall energy consumption by sensing to prolong the whole network?s life time, and at the same time to achieve the high ratio of coverage. Extensive simulation is conducted to verify the effectiveness of our node scheduling models.