This thesis presents the process of creating a mobile application for viewing wireless sensor data. We have used an existing wireless sensor network, developed at "Jožef Stefan" institute. The sensor network nodes were upgraded to also measure relative humidity. During the upgrade we noticed a number of bugs in the firmware and fixed them. We developed a Raspberry Pi platform which parses the data from the sensor network into a local database. The platform also serves the data using a web API. The mobile application was developed using Android studio. The application displays the sensors on a floor plan with colors representing the temperature or humidity. The application also displays graphs for viewing historical data. The platform was co...