Be safe with Android application.
Bipper bSafe, is an app on Androids that was created for the safety of women walking alone at night or in situations where there's no escape, and for a few men as well .bSafe is always with you, packed with features designed to make you feel safe. When you trigger the alarm the phone automatically calls a pre defined friend. In addition a text message with a link to a map with your location is sent to as many friends as you like. This way they know you need help or assistance and how to find you.
When you trigger the alarm, the phone also simulates an incoming call. Which means once you trigger it, if an offender gets his hand on your phone he won't be able to see the application, all he sees will be an incoming call.
Cleaver and cool.