The use of wireless sensor networks for monitoring and surveillance has gained attention in the past few years. The main challenge experienced in these network applications is how to guarantee a suitable level of coverage such that every target or event is observed. In this paper, a new fuzzy logic based scheme is proposed in order to build the set covers. The computations of this centralized scheme are done on the Base Station. The main goal is to determine a portion of the sensor nodes that must go into active mode to satisfy the coverage requirement. All other nodes will switch to sleep mode until the next round.