Indoor orientation and navigation in buildings and underground public transport is still a challenge. A key problem is the determination of the levels, e.g. floors and platforms, especially in environments with large amount of balconies and more or less levitating escalators, lifts and stairs. Another desired application is navigation or at least orientation in public undergrounds, which is missing due to missing common available sensors. GPS is not available in tunnels. Wifi cells are very unusual at least in the Berlin underground environment. Infrastructure based sensors and communication would be able to solve a personal navigation, but requires investments. With the introduction of barometer as a sensor in the Android 2.3 API and the first available Android mobile phones with build-in barometer sensors (Xoom and Galaxy Nexus), pressure can be used to calculate altitudes or even more relevant to measure pressure differences, e.g. between building levels and stations. This talk is intended to give and get a feeling about the given accuracy and robustness in relation to indoor positioning for buildings and undergrounds and should report about the ongoing, but already promising experiments.