Bumping/file sharing applications

[cromartie]

Guys,

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.

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

Thank you in advance

 

[JonPM]

They probably just use the gps. Its not the wifi because I've used these apps with the wifi turned off. Its a simple concept really: send each active users gps coordinates to a server, and if they are within a few feet of each other then "link" them up. All "link" means is that when they bump, send the data from one phone to the cloud and down to the other phone.

Sent from my DROIDX using Tapatalk

 

[Erel]

You can find "bumps" using the accelerometer. Similar to finding shakes: Android shake event with PhoneSensors

Together with the location (based on GPS or cellular position) you can find matching devices.