Android bumping/file sharing technology
<p>There are a number of applications on the market that allow Android phones to exchange files or some other information. Those applications usually rely on two Android devices being in close proximity and detecting each other's presence. I do not think that they use bluetooth communication to send signal to each other since bluetooth can be off and it would take some time to activate it so bumping would take longer than it does in those applications. Thus those apps have to use some other sensors that most of android phones are equipped with.</p>

<p>Do you have any idea of what those sensors are and how the phones become aware of each other's presence?</p>

<p>Thank you in advance</p>
