Developments in cost-effective sensor architectures have made Wireless Sensor Networks (WSNs) a new and popular filed of research. A wireless sensor network is created by randomly placing a large number of limited-capacity, low-cost, low-power sensors with a short range transmitter in an environment which is not easily accessed and mostly unsafe. WSNs are therefore used in a wide range of fields from healthcare field to military field, securing a building to pre-detection of forests fires. The detected data from an environment monitored by sensor nodes need to be analyzed and observed in many applications where a WSN is used. In this study, a safe monitoring system was developed for WSNs using TelosB sensor nodes. The data collected by sensor nodes is encrypted in 128 bit and transmitted to the server. With this safe monitoring system, detected light, humidity and temperature values from the environment are analyzed by web media and monitored by visual graphs. In addition, WSN can be monitored via mobile platforms by means of smart telephones that are increasingly used due to advancing technology.