iBeacon calculate distance in meters

iBeaconCalculateDistance.js

// Based on http://stackoverflow.com/a/20434019

function calculateAccuracy(txPower, rssi) {
  if (rssi === 0) {
    return -1; // if we cannot determine accuracy, return -1.
  }

  var ratio = rssi * 1 / txPower;
  if (ratio < 1.0) {
    return Math.pow(ratio, 10);
  } else {
    return (0.89976) * Math.pow(ratio, 7.7095) + 0.111;
  }
}

Could you maybe add an example of how to exactly use your function?

I have an iBeacon that is 1m away. I have a txPower of 4dbm and an RSSI of -55dbm. But when I put these values into your function I get these results:

calculateAccuracy(4,-55)
// 241561090582.98172

So instead of approximately 1m i get 0.02502742130697 mili-lightyears

@besi The TX power is not what you think it is. Its the dbm value at a distance of 1m (for calibration). You can also read it from an iBeacon when its correctly calibrated.

So in your case you have to call calculateAccuracy(-55,-55) and you will get 1,01m
So in your case you have to call calculateAccuracy(-55,-80) and you will get 16,27m

Why do you multiply for 1?

@philipgiuliani how did you get to txPower of -55 ?

@navyseai
please reference it
https://stackoverflow.com/questions/20416218/understanding-ibeacon-distancing

This formula for iOS devices ? How is for android ?

This formula for iOS devices ? How is for android ?

@hadpro24 sorry I have no idea, I have used this function once in 2015 and have forgotten the context 🤷‍♂️