RSSI to Distance Conversion

gistfile1.js

function calculateDistance(rssi) {
  
  var txPower = -59 //hard coded power value. Usually ranges between -59 to -65
  
  if (rssi == 0) {
    return -1.0; 
  }

  var ratio = rssi*1.0/txPower;
  if (ratio < 1.0) {
    return Math.pow(ratio,10);
  }
  else {
    var distance =  (0.89976)*Math.pow(ratio,7.7095) + 0.111;    
    return distance;
  }
} 

@totterfree Not sure how those values came to be but do read the answer in the stackOverflow post
https://stackoverflow.com/a/20434019/2104970

Not accurate, 0.89976, 7.7095 and 0.111 are average numbers

When I tested your code on my application, I was 2 meters far from the sender and the function returned a distance of 0.0829... . The rssi was -46dB. It seems like I should change the variable txPower much under -59. If anyone has an idea for my problem

Your code says that if you receive less than -59dB, then the sender is at most 1 meter far from you. Whereas after testing on my experience -59dB represents a longer distance