—Wireless Sensor Networks (WSNs) consist of spatially-distributed autonomous sensors that can cooperatively monitor physical and environmental conditions. Because of sensors’ resource-constraints in terms of size, power, and bandwidth, one of the fundamental objectives in WSNs is improving energyefficiency. In this paper, we propose a mesh-based technique to obtain energy-efficiency in sensing and improve the quality of coverage. Our technique dynamically schedules a set of active sensors based on a square mesh or an equilateral-triangular mesh. The purpose of our technique is to quickly build an energy-efficient mesh that is self-adaptive to the local topology and allows energy balancing. Furthermore, a hole detection and recovery mechanism is discussed to guarantee full coverage. The simulation results confirm that our mesh-based coverage technique reduces sensing energy consumption and maintains a sound coverage ratio for reliable surveillance. Key words: wireless sensor net...