Modern home security devices are loaded with sensors. So is your old phone. Only one is basically free. Haven turns any old Android device (running 4.1 or later) into an intelligent monitoring solution. Crafted in collaboration with Edward Snowden, it's meant to help protect journalists, whistleblowers, or anyone else at risk of forced disappearance. You can set it up to detect sound, motion, or both, and tell it to record video once it's set off, catching any would-be assailant with either the front or rear camera.