PressureNet uses sensors in Android devices to collect live data about the atmosphere. The app runs periodically in the background to measure atmospheric pressure (via onboard barometer) and location, which it then stores and sends to PressureNet servers. This live data is relayed directly to researchers who are working to improve weather forecasting.
This app is built using the open source PressureNet SDK, which does much of the heavy-lifting for periodic data collection and transmission.