title: Distance between bluetooth module and an android device
body: <p>I'm trying to calculate the distance between and android device and  the HC-05  bluetooth module (connected to an arduino module: the MEGA 2560), using an android app created using appinventor.</p>
  
  <p>For example I'd like to know if the devices are 4 meters from each other so I can turn on an alarm.</p>
  
  <p>After doing some research it seems that is almost imposible to do, it seems that the most that can be done is estimate that distance constantly sensing the RSSI indicator.</p>
  
  <p>Is this possible? if not ,what could I use?</p>
  
  <p>Are the elements of my project (HC05,arduino, appinventor) the ones I should be using?</p>
  
  <p>Is this the only way?</p>