I am using android beacon library to detect beacons.I have created a service which implements Bootstrap Notifier and It got two methods :
#Override
public void didEnterRegion(Region arg0) {
Log.i(TAG, "A beacon has enter the region .........");
}
#Override
public void didExitRegion(Region arg0) {
Log.i(TAG, "A beacon has exit the region .........");
}
and also :
mAllBeaconsRegion = new Region("all beacons", Identifier.parse(UUID),null, null);
mBeaconManager = BeaconManager.getInstanceForApplication(this);
new BackgroundPowerSaver(this);
bootstrap = new RegionBootstrap(this, mAllBeaconsRegion);
mBeaconManager.setBackgroundScanPeriod(1000l);
mBeaconManager.setBackgroundBetweenScanPeriod(1000l);
My problem is that in some devices beacon exits the region automatically and didExitRegion called and then re-enters in region and didEnterRegion called.It again disconnects automatically.
This is happening in loop. I am testing it with Lollipop.
How can i get rid of this?
Please help.
It is important to understand what causes a Region exit. A region exit fires when no advertising packets from a beacon matching a Region object are detected in a 10 second period. There are a number of things that can cause this:
Hardware beacons that do not advertise frequently enough. For best performance, beacons should advertise at a rate of 10 Hz or more. Some manufacturers slow down the advertising rate to save battery, making beacons advertise only every 5 seconds or so. This can cause region exits if some of the packets are missed by the receiver due to radio noise or other issues. To solve this problem, configure your beacon to advertise at least once per second (1 Hz.)
Beacons being on the edge of the radio range of the mobile device. Bluetooth beacons have a varying range of 2-50 meters, depending on the manufacturer, settings, placement and the antenna on the receiving mobile device. If the signal is very weak, detections an be intermittent, causing exits if no packets have been seen in 10 seconds. To fix this, increase the transmitter power of your beacon, or add a software filter to ignore intermittent exit events.
Some mobile devices (e.g. Moto X, Moto G, Nexus 4, Nexus 7) have a hardware flaw where bluetooth and WiFi do not work simultaneously. This can cause the symptoms you describe because it makes beacon detections intermittent. To solve this problem, disable WiFi when looking for beacons on one of these devices.
Related
I created an android (java) application that uses the altbeacon library (github page) to detect beacons via the Bluetooth module.
The Beacons are configured with Eddystone UID, protocol with an advertising interval of 100ms and transmit power level of strong (10dBm).
What I would like to be able to do is to detect the RSSI value of the beacons with a frequency of 10Hz (i.e. 100ms).
I've already prepared a service that implements the altbeacon library, the relevant part are showed below:
mBeaconManager = BeaconManager.getInstanceForApplication(this);
beaconRegion = new Region("beacon_region", null, null, null);
// use Eddystone protocol
mBeaconManager.getBeaconParsers().add(new BeaconParser().
setBeaconLayout(BeaconParser.EDDYSTONE_UID_LAYOUT));
mBeaconManager.setAndroidLScanningDisabled(true);
mBeaconManager.setForegroundScanPeriod(100l); // scan frequency
mBeaconManager.setForegroundBetweenScanPeriod(0);
and the callback didRangeBeaconsInRegion from which I see the beacons and get the RSSI value is this:
#Override
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
Log.i(BeaconDataCollectorService.class.getSimpleName(), String.format("Found %s beacons in range", beacons.size()));
}
What's my problem?
Running the app, I notice that within didRangeBeaconsInRegion, I often don't see all the beacons.
I ran the data collection for a few seconds, creating a csv format of the data obtained, where you can see that I often have 0s (indicating that the beacon was not detected); I put the sharing of this csv on pastebin (https://pastebin.com/zkUZC5R4)
How can I improve the scan frequency by always being able to detect all the beacons?
altbeacon version used:
implementation 'org.altbeacon:android-beacon-library:2.16.3'
Android version: 9
Thanks
Unfortunately, the library is not designed to do this, as the ranging APIs are modeled after iOS equivalents which give aggregate detections at fixed intervals as opposed to access to individual packets when they arrive.
The main reason you often get 0 beacons detected with such a short scan period is because the scan is turned on and off every 100ms, and it takes 10ms or so to start and stop. This gives a good probability of missing the detection.
Here's the good news: If the library ever detects two beacon packets in the same scan period then it will stop turning the scan off and your detection rate will improve. But getting it to detect two beacons in 100ms is nearly impossible of your beacon advertises at a nominal 10Hz.
One thing you might try is to start by setting the scan period to 1 second. After you have detected a finite number of your beacons for 10 secs or so, there is a very good chance you will have detected two beacons in one scan cycle and then you can switch to a scan period of 100ms and get a higher detection rate.
You will never get a 100% detection rate for two reasons:
Not all beacon packets transmitted are received due to collisions and radio noise. At close range 80-90% is typical.
"BLE advertisers do not advertise at regular intervals. They randomize when their packets are sent to avoid collisions. A nominal 10Hz transmitter might have anywhere between 70ms and 140ms between individual packets, so for fixed scan cycles of 100ms sometimes there will be 0, 1 or 2 Packers eligible to be received.
If you really need to get callbacks on every detection, you might try setting up a NonBeaconBleScanCallback in the BeaconManager, then calling BeaconManager.clearBeaconParsers(). This will cause all beacons detections to be sent to that callback immediately when detected. You will then have to construct a new BeaconParser for use inside that callback to decode the beacon from the raw packet. Use beaconParser.parse(...)
I use android phone to detect a beacon using startScan method, the interval time of beacon adversing is 800ms, but I got the beacon data from callback of startScan every 3~10 seconds. My expectation is I can get the data every 1 second.
Below is my codes. So is there any other ways to get my expectation. Or someone can explain why the interval time is not the same as the adversing time ?
ScanSettings.Builder builder = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY);
// scan filters has been set the right value.
bluetoothLeScanner.startScan(scanFilters, builder.build(), scanCallback);
Nothing about the code shown is a problem. I can confirm your expectation is met with equivalent code in other apps on other devices. This suggests a problem with :
Your BLE device not advertising as often as you expect
Your Android phone (possible but unlikely)
Some other aspect of your code that you did not show in your question.
Is you BLE device a beacon? If so, I suggest:
Install BeaconScope on the same phone, scan for your beacon, then check the PPS rating (Packets Per Second -- scan for at least 30 seconds until the measurement stabilizes). If you see a value of 0.1-0.3 then the problem is NOT with your code and must be (1) or (2). If you see a much higher PPS value, the problem is with some other aspect of your code not shown.
Use a second Android phone with BeaconScope as a transmitter and transmit a beacon at the 10 Hz default rate. Does your app get a packet every 100-200ms? If so, you have confirmed the problem is with your BLE device not transmitting as much as you expect.
If your BLE device is not a beacon you can at least perform the second test.
It's recommended to use 'SCAN_MODE_LOW_LATENCY' mode only hen the application is running in the foreground.
Incase you are in background, you can run a sticky foreground service and set a periodic frequency of 1 sec for your service.
Also scanning Ble for every 1 sec might be extremely heavy for the app.
Hello I am poor at English.
I use Android Beacon Library
implementation 'org.altbeacon:android-beacon-library:2.15.2'
My Android application gradle imformation
compileSdkVersion 28
minSdkVersion 21
targetSdkVersion 28
My Beacon manager information
beaconManager.getBeaconParsers().add(new BeaconParser().setBeaconLayout("m:2-3=0215,i:4-19,i:20-21,i:22-23,p:24-24"));
beaconManager.setForegroundScanPeriod(1100L);
beaconManager.setBackgroundScanPeriod(1100L);
beaconManager.setForegroundBetweenScanPeriod(0);
beaconManager.setBackgroundBetweenScanPeriod(0);
beaconManager.enableForegroundServiceScanning(notificationcompatBuilder_Scannging.build(),456);
beaconManager.setEnableScheduledScanJobs(false);
BeaconManager.setDebug(true);
regionBootstrap = new RegionBootstrap(this, myBeaconRegion);
Error
I want to develop all day beacon scanner application.
So I use regionBootstrap to scan in background.
It looked like it was working.
However time passed and Exit Event suddenly occurred and Enter Event occurred shortly after.
I think scan does not work for a few seconds and I have conducted a test on this.
Error Test 1
one smartphone , two beacons
Error1
One beacon signal is not detected for more than 10 seconds while another beacon signal is detected.
So I think scan work well and it is a problem of beacon.
Error Test 2
two smartphone , two beacons
smartphone 1
enter image description here
smartphone 2
enter image description here
In smartphone 1 Logcat, Also One beacon signal is not detected for more than 10 seconds while another beacon signal is detected.
In smartphone 2 Logcat, Unscanned beacon is being scanned at the same time.
So beacon does not problem and I can't find reason.
Error Test 3
Added test
two smart phone
My beacon transmit the signal about once every three seconds.
In smart phone 1, download the other beacon application which has beacon signal transmit and transmit at 1Hz.
In smart phone 2, by using my application, watch the signal.
enter image description here
The beacon signal of smart phone 1 increase markedly, but the same problem arose.
Does anyone know about this matter?
I want a help...
Please
I suspect that the beacons you are using to test are not transmitting frequently enough. Manufacturers often reduce the transmission rate to save battery. When the transmission rate gets below 1Hz, this can cause problems, because not 100% of beacon packets transmitted are received by any phone. Radio noise often causes packets to be missed. If one device misses a few packets in a row (it happens sometimes) it causes a region exit event.
The solution is to increase the frequency at which the beacons transmit. With some manufacturers this is configurable. With others, it is not. If it is not configurable, you may need to buy different beacons
You can test if this is the problem by using an Android beacon simulator app on one of the devices. Try my BeaconScope app, which will advertise at 10Hz by default.
This library return result only when a specific event is triggered, not for all beacon scanned.. if you need this I suggest you to use the standart android standard beacon library, if you want to know more about this and how to implements comment this post and I'll edit it with the implementation
I am developing an Android app that scans for BLE devices periodically, and use the beacon information for further processes. I need to catch the Beacon which is closest.
// Scan for bluetooth devices and parse results
private void scanLeDevice() {
// Stops scanning after a pre-defined scan period.
if(!mScanning){
Handler mHandler = new Handler();
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
Log.d(TAG, "stop scanning");
mScanning = false;
mBluetoothAdapter.stopLeScan(mLeScanCallback);
Log.v(TAG, "closing scan. beacon found:" + beaconFound);
broadcastLocalUpdate();
beaconFound = false;
stopSelf();
}
}, SCAN_PERIOD);
proximity=null;
totalDevices=0;
mScanning = true;
mBluetoothAdapter.startLeScan(mLeScanCallback);
Log.d(TAG, "start scanning");
}
}
The beacons I use:
Emit an advertisement 3x each second
Emit over 3 different channels
I have over 5 in a room
On one of my test devices, the Sony Xperia z2, this works. I get a long list of devices with Beacon information and RSSI values. each Beacon is discovered multiple times each scan.
On my other test device, the Motorolla Moto G(2nd generation), this scanning behaves WILDLY UNPREDICTABLE. On most scans only 2 or 3 devices are discovered. Other occasions it discovers about 10 devices (includes duplicates). It does not matter whether these devices are close or far.
Is this a software issue or a hardware issue?
How can I improve the results of a BLE scan?
Your beacons are not advertising frequently enough, creating a very real chance that no transmission occurs while the receiver is monitoring on its frequency. Try for at least 10 transmissions a second, but preferably more if you have an external power source.
Of course it is not all in the transmitter - Android phones vary drastically in how much they receive to detect BLE advertisements, and may report drastically different signal levels under the same conditions.
You may want to collect results over several scans in a short period, and look at the aggregate data, not just that of a single scan.
The scan result is for each received adv. No matter what rssi.
The antenna is a shared resource on most phones.
Wifi, bt classic, ble. So the phone only listens for adv in windows. Only if the adv falls into this window will get callback. The phone must listen on 3 channels.
So try playing with your adv interval and adv package size. If you have many in the same room you should not use too fast adv interval as the adv channels will be filled and collisions will occur.
Try turning off wifi and retest.
Avoid having classic bt connection.
Put name in scanresponse if you can to keep adv package short.
What I need is to get a list of every devices in my range so I can call a certain method on them one after another.
What I have tried so far is to use the startDiscovery() method of the BluetoothAdapter and while it returns a list of devices it takes about 12 seconds to complete which is a lot for my task to complete.
I also managed to user the LeScanCallback succesfully every 2-3 seconds and I do discover devices, but on every scan it returns only one device at a time.
I'm trying to search for Beacons so this type of method could return every call a single other device that uses BlutoothLE when it's found ,while not returning my Beacon's info at all.
So, is there a way to discover a list of all devices in a range without waiting for the startDiscovery() to finish after 12 seconds ?
A few points:
startDiscovery is intended for bluetooth classic devices, not Bluetooth LE.
Android does not contain any APIs specific to parsing beacons, only for dealing with raw Bluetooth LE devices.
You can use the free and open source Android Beacon Library add-on to detect and parse beacons. It does not have a 12 second delay and wraps the LeScanCallback method and combines the results so you can get callbacks every second like:
public void didRangeBeaconsInRegion(Collection<Beacon> beacons, Region region) {
for (Beacon beacon : beacons) {
Log.i(TAG, "I see a beacon:"+beacon+" that is "+beacon.getDistance()+" meters away.");
}
}
You need to call startScan(ScanCallback) api of BluetoothLeScanner to start scanning, this has support on Android 21(5.0).
Also look below question, it has sample code you can use to start/stop Le Scanning.
How to restart BluetoothLeScanner?