Apologies - shall post source soon. Making some rather major changes, including but not limited to: Now works on altitude above terrain rather than sea-level Three alarms - one for either excessive descent rate (auto mode) or descent when below a specified altitude (manual mode, similar to how it works now) Alarm when dropping below 152 meters (500 feet-ish) Alarm when you're about to hit the deck and probably explode. A few other tweaks too, Manuxkerb, hopefully the sound will work for you in the new version, not certain what the issue might have been but it could be related to how it was checking your altitude before (ie. against sea level rather than terrain). Thanks