com.gallagher.security.mobileaccess.ReaderDistance Enum Reference

Public Member Functions
	ReaderDistance (int value)
int	getValue ()

Static Public Member Functions
static ReaderDistance	parse (int i)
static ReaderDistance	calculate (double txPower, double autoConnectPathLoss, double manualConnectPathLoss, double measuredPathLoss)

Public Attributes
	NEAR =(0)
	MEDIUM =(1)
	FAR =(2)

Detailed Description

If Bluetooth signals are visible from multiple readers at a given physical location, ReaderDistance can be used to infer which reader is physically closer to the phone.

Note: These values do not adhere to any particular unit of measure, and two phones in the same play may disagree on values for a given reader due to the margin of error inherent in measuring a Bluetooth signal. If you use them, you should only do so in an abstract way, such as showing different colored icons for a near vs far reader.

Constructor & Destructor Documentation

ReaderDistance()

com.gallagher.security.mobileaccess.ReaderDistance.ReaderDistance

(

int

value

)

                              {
        mValue = value;
    }

Member Function Documentation

calculate()

static ReaderDistance com.gallagher.security.mobileaccess.ReaderDistance.calculate ( double  txPower, double  autoConnectPathLoss, double  manualConnectPathLoss, double  measuredPathLoss  )

static

                                                                                                                                                {
        if(manualConnectPathLoss <= 0) { // if manual connect is disabled we never see the reader until we're right on top of it
            return NEAR;
        }
        // 100 is the "max" RSSI we've seen in testing, so adjust the max PL we think we should theoretically see
        double manualPL = Math.min(manualConnectPathLoss, 100 + txPower);
 
        // although you can configure auto pathloss down to 1, I've never seen lower than about 15 or so. Use this as our lower limit
        double autoPL = Math.max(15, autoConnectPathLoss);
 
        double plRange = manualPL - autoPL;
        if(plRange < 5) {
            // if the difference between manual and auto connect range is small, we're not really going to get a meaningful value
            // also this prevents a possible divide-by-zero below
            return NEAR;
        }
 
        double plInRange = measuredPathLoss - autoPL;
 
        double result = plInRange / plRange;
        if(result < 0.4) {
            return NEAR;
        } else if(result < 0.75) {
            return MEDIUM;
        } else {
            return FAR;
        }
    }

getValue()

int com.gallagher.security.mobileaccess.ReaderDistance.getValue

(

)

                          {
        return mValue;
    }

parse()

static ReaderDistance com.gallagher.security.mobileaccess.ReaderDistance.parse ( int  i )

static

Returns null if the int can't be parsed

                                                        {
        for(ReaderDistance r : values()) {
            if(r.mValue == i) {
                return r;
            }
        }
        return null;
    }

Member Data Documentation

FAR

com.gallagher.security.mobileaccess.ReaderDistance.FAR =(2)

The SDK believes this reader is far away

MEDIUM

com.gallagher.security.mobileaccess.ReaderDistance.MEDIUM =(1)

The SDK believes this reader is a medium distance away

NEAR

com.gallagher.security.mobileaccess.ReaderDistance.NEAR =(0)

The SDK believes this reader is close to the phone

---

The documentation for this enum was generated from the following file:

• ReaderDistance.java