Wireless Sensor Networks (WSNs) are spreading around in multiple fields of applications because they perform measuring tasks in a flexible way . In this presented work IEEE 802.15.4 protocol based Zigbee transceivers module are used to make the wireless sensor network. The sensor node will acquire and internally store data periodically. Starting times as well as the time intervals for the measurements can be freely programmed over the network system . As soon as a mobile network is detected in its proximity the node will automatically transfer data. Optionally sensor data can be delivered on demand. When in its idle state the node remains in power-down mode in order to minimize power consumption. The system is based on an AVR microcontroller coupled to an RF-transceiver. In a sample application the system is interfaced to a piezoresistive pressure sensor, typically used to determine water levels in closed tanks or open aquaculture systems. Possible applications in the area of environmental monitoring will be presented (including tidal range measurements).