The philosophy behind this app is to use your android phone as a flight instrument without taking it in sight, but in the pocket of your flying suit or harness. This brings comfort (you don’t need cockpit) and autonomy (screen on draws too much power from the battery) to your flights. You should use wired or bluetooth headphones or a handheld remote speaker microphone (RSM) to listen the vario tones and voice messages generated by the app. For those phones which have not a built-in pressure sensor the app has full BlueFlyVario module support.
Apart from your climb ratio theairdroid variometer tells you the wind speed and direction when them change, the altitude when you leave a thermal and when to accelerate or brake to keep up the optimum speed given by the polar curve of your glider. You will also know when you have enough altitude to reach the take-off.
If you purchase "enable button" update you could ask the app for all this info pressing the button of your hand-held speaker or headphones. You could know your current course and the course, altitude and time required to reach whatever waypoint of the task loaded previously.
The app uses INTERNET android permission to allow subscriptions, not for showing banners or ads, neither to send personal information over internet. Android permission READ_PHONE_STATE is used to mute the vario while answering a phone call.
For more info go to the app website. Read the operating intructions in the manual posted in the website prior to use it.