Develop Reference

How can I use the Magnetometer from this Sensor API?

I'm trying to get use the magnetometer from this Sensor API but I'm not sure if I'm doing so correctly.
I copied and edited the example code from the their site into my test site;
let sensor = new Magnetometer();
sensor.start();
sensor.onreading = () => {
console.log("Magnetic field along the X-axis " + sensor.x);
console.log("Magnetic field along the Y-axis " + sensor.y);
console.log("Magnetic field along the Z-axis " + sensor.z);
document.getElementById("x").innerHTML = "X = " + sensor.x;
document.getElementById("y").innerHTML = "Y = " + sensor.y;
document.getElementById("z").innerHTML = "Z = " + sensor.z;
};
sensor.onerror = event => console.log(event.error.name, event.error.message);
But when I load the page it doesn't give me any readings. Checking the site on my laptop brings back this error message;
Uncaught ReferenceError: Magnetometer is not defined
at magnetometer.js:1
Any insight into this would be greatly appreciated.

I found the answer. After looking around I found that you need to go to chrome://flags/#enable-generic-sensor-extra-classes and enable Generic Sensor Extra Classes.
I'm not sure why this is the case but I am now getting the readings I was after.

How to increase the delay in the data of the region notifier?

I have using Android Beacon Library for one of my beacon solution .Is there a way put a delay in data produced by the range notifier because it is giving data very frequently .
Below is the code which I am referring to. To see complete code you can go to this thread "Android iBeacon App not working in the background"
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
if(beacons.size() > 0) {
for (Beacon beacon : beacons) {
if (beacon.getDistance() < 1.0) {
Log.d(TAG, "I see a beacon transmitting a : " +
" approximately " + beacon.getDistance() + " meters away.");
Log.d(TAG, "BEACON DATA : " +beacon.getBluetoothAddress()+":"+beacon.getBluetoothName()+":"+beacon.getId1());
showNotification("Treewalker","You are near beacon range");
Intent intent = new Intent(this,MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
this.startActivity(intent);
}
}
}
}

There are two methods which can help you
mBeaconManager.setBackgroundBetweenScanPeriod(10000);
mBeaconManager.setForegroundBetweenScanPeriod(10000);
Check official javadocs for details

How to detect multiple beacons using Altbeacon android library?

I am using the AltBeacon sample app on my android device - the sample app provided by altbeacon.org is here: https://github.com/AltBeacon/android-beacon-library-reference
However, the app when launched is detecting and displaying only one beacon. I have about 5 beacons near my Android device. How do I detect all the beacons?
In RangingActivity.java, I noticed this method that is being called when a beacon comes in sight:
public void onBeaconServiceConnect() {
beaconManager.setRangeNotifier(new RangeNotifier() {
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
if (beacons.size() > 0) {
EditText editText = (EditText) RangingActivity.this.findViewById(R.id.rangingText);
Beacon firstBeacon = beacons.iterator().next();
logToDisplay("The first beacon " + firstBeacon.toString() + " is about " + firstBeacon.getDistance() + " meters away.");
}
}
}
I modified the iterator to read from the collection in a while loop as follows:
Beacon firstBeacon;
while(beacons.iterator().hasNext()){
firstBeacon = beacons.iterator().next();
logToDisplay("The first beacon " + firstBeacon.toString() + " is about " + firstBeacon.getDistance() + " meters away.");
}
However, the app crashes with this modification.
My questions:
(1) How can I display all beacons that are near my Android device?
(2) How can I detect beacons that go out of region?

For 1. I think you need to use a For loop. Like this.
for (Beacon beacon : beacons) {
logToDisplay("The beacon " + beacon.toString() + " is about " + beacon.getDistance() + " meters away.");
}
For 2. I was having trouble detecting that, but it might be a long timeout. So be very patient. I think the code in the Monitoring activity can be altered to display a message for that. Or you can review the logcat from a device.
A simple logToDisplay can be used inside the didExitRegion section of BeaconReferenceApplication.
public void didExitRegion(Region region) {
if (monitoringActivity != null) {
monitoringActivity.logToDisplay("I no longer see a beacon in the "+region.getUniqueId());
}
}

Interpreting BluetoothGatt Value from Light Sensor

I am writing an app which is receiving values from a Light Sensor of a BLE device. I am trying to determine what it is that I am receiving. I am trying to get the Lux value which is provided by the sensor, but am concerned that it needs conversion. I do not know what the unit of measure is for this sensor. For example, the unit for an Android phone is SI Lux. Should be easy enough, but for this sensor, the specs do not state.
Here is the code which is giving me output:
case MSG_LIGHT:
characteristic = (BluetoothGattCharacteristic) msg.obj;
if (characteristic.getValue() == null) {
Log.w(TAG, "Error obtaining light value");
return;
}
int formatlgt1 = -1;
formatlgt1 = BluetoothGattCharacteristic.FORMAT_SINT8;
Log.i(LIGHT, "Light RawValue1 " + characteristic.getIntValue(formatlgt1, 0));
Log.i(LIGHT, "Light RawValue2 " + characteristic.getIntValue(formatlgt1, 1));
Log.w(LIGHT, "Light UUID " + characteristic.getUuid());
Log.w(LIGHT, "Light Stored Value " + characteristic.getValue());
Log.w(LIGHT, "Light Descriptors " + characteristic.getDescriptors());
Log.d(LIGHT, "Light Characteristic " + characteristic);
updateLightValues(characteristic);
break;
Simple enough, just read the sensor and give me the various outputs from that sensor at the time of reading. Next here is the output:
Light RawValue1 4
Light RawValue2 9
Light UUID 0000aa91-0000-1000-8000-00805f9b34fb
Light Stored Value [B#431d30b0
Light Descriptors [android.bluetooth.BluetoothGattDescriptor#4300e508, android.bluetooth.BluetoothGattDescriptor#4300eaf8]
Light Characteristic android.bluetooth.BluetoothGattCharacteristic#43002b10
I am interpreting that the measurement of this is the RawValues 1 & 2 but am logging what is stored to help. Problem is that the StoredValue is [B#431d30b0 which is beyond me. According to the description form the manufacturer, it states that the first byte is the HILUX at address 00x03 and the second is LOLUX at address 00x04 with a default value of 00:00.
What am I looking at here and where am I going wrong? Where I am hurting is my understanding of what I am reading. Can't seem to get a good search context to learn about it.
Thanks

How can I get exact GPS location with AIR Geolocation API?

How can I get the exact Latitude and Longitude? I only get whole numbers. From my understanding, in order to get down to the meter I need to get down to 5 decimal places. I have tried the horizontal and vertical accuracy but they don't match my phones GPS reading.
How can I get an exact GPS reading with Geolocation API, Down to the meter?
here is my code
var my_geo:Geolocation = new Geolocation();
my_geo.setRequestedUpdateInterval(2000);
my_geo.addEventListener(GeolocationEvent.UPDATE, onGeoUpdate);
function onGeoUpdate(e:GeolocationEvent):void
{
gpsLat1 = (e.latitude);
gpsLon1 = (e.longitude);
gpsHeading = (e.heading);
gpsHorAcc = (e.horizontalAccuracy);
gpsVerAcc = (e.verticalAccuracy);
gpsCheck = 2;
my_txt.text = "My Latitude is "+ gpsLat1 + " and my Longitude is "+ gpsLon1 + " Bearing is " + gpsHeading+ " HorAcc "+ gpsHorAcc+ " VertAcc "+gpsVerAcc;
}

Make sure your variables (gpsLat1, gpsLon1, gpsHeading, etc.) are of type Number and not a uint or int. Unsigned Integers and Integers only allow for whole numbers, whereas Number is the equivalent of float in most other languages (and allows for incredibly larger values, as well). If you save a decimal to an integer, it is rounded off/floored (I can't remember which), which sounds exactly like the problem you are having.
Alternatively, the API is restricted by the hardware you are testing on. If the hardware only returns a certain value for GPS coordinates, AIR cannot be any more precise. Odds are this is not the issue since a whole lat long point can be miles and miles in distance, meaning any device with that inaccurate of a GPS chip is absolutely useless.

Try this:
function onGeoUpdate(e:GeolocationEvent):void
{
gpsLat1 = (e.latitude.toString());
gpsLon1 = (e.longitude.toString());
gpsHeading = (e.heading.toString());
gpsHorAcc = (e.horizontalAccuracy.toString());
gpsVerAcc = (e.verticalAccuracy.toString());
gpsCheck = 2;
my_txt.text = "My Latitude is "+ gpsLat1 + " and my Longitude is "+ gpsLon1 + " Bearing is " + gpsHeading+ " HorAcc "+ gpsHorAcc+ " VertAcc "+gpsVerAcc;
}