Android: There are a lot of 'in case of emergency' SOS apps on the Play Store, but the onus is usually on the phone owner to hit a button or tap something. SafeSpot takes a different approach, turning your Android into a virtual dead man's switch which sends out an SOS text message if you let go of your screen.
The app's idea is that you'll know when you are in a dangerous area. If that's the case, start SafeSpot and select one of the preset contact groups you created. A yellow dot appears at the bottom of the on screen. Drag the dot up and it turns orange. If you let go of the screen when the dot is orange, an SOS is sent out to all the people in your contact group. If you think you're safe, just drag the dot back to the bottom till it turns yellow.
The only catch is that you need to make sure your GPS is turned on as SafeSpot needs to send a text message with your GPS coordinates. In my tests, when GPS was off, the app couldn't get a reading and crashed.