Air raid warning tech gives Syrians life-saving minutes Syrians subscribe to a warning system that alerts them on their phones of the incoming threat of air strikes in Syria's rebel-held province of Idlib, giving residents more time to take cover. The Sentry programme, launched two years ago by two Americans and a Syrian coder, uses human observers and a network of sensors to compute a predicted impact location when Syrian or allied Russian warplanes take off. IMAGES AND SOUNDBITES