A body sensor network is a network of small sensor devices (biosensors) that sense health parameters of an individual, allowing 24/7 monitoring, providing biofeedback services. These networks have typically two layers: the sensor array and a sink node. The sink node manages the network, gathering sensor data continuously. However, raw sensor data is not enough to achieve biofeedback. One of the challenges body sensor networks present is the processing of raw biosensor data, in order to achieve a proper medical visualization of monitored parameters. This paper surveys some of the current approaches, proposes an interface classification based on features, and presents a solution based on a mobile device. The mobile application can run on a Java and Bluetooth enabled phone, allowing data retrieval, storage and analysis in a single solution. The mobile application proposes a three-layer approach to BSN operation, adding the mobile device to the solution. The final system provides the user with a completely functional health-monitoring platform, which is easy to use and setup, validated through a complete series of tests on different mobile devices.