I am developing several applications that make use of scanning devices ibeacons. Each application has a different scanning frequency. my question is whether there can be a problem to be multiple applications simultaneously scanning. What is the access protocol to stack bluetooth devices?.
In addition, I have a service running in the background which performs periodic scans and in all the devices I've tested the application works properly except one, the new Moto X. the application is blocked and does not perform scans. Any ideas??
thank you very much in advance!!
The Android Beacon Library allows multiple applications to scan for beacons simultaneously without interfering with each other. This works because the Android BLE scanning APIs keep track of which apps are doing a scan. If Application A and B both start a scan, and Application B stops its scan, the operating system keeps scanning and sending results to Application A.
To prove this point, I installed two different copies of the BeaconReferenceApplication on a Moto G running Android 4.4.3. The application package name was modified slightly to allow simultaneous installation, and the default scan rate was set to 5 seconds on/off on Application A, and 10 seconds on/off on Application B. The application customizations are shown below:
Application A
long scanPeriod = 10000l;
long betweenScanPeriod = 10000l;
mBeaconManager.setBackgroundBetweenScanPeriod(scanPeriod);
mBeaconManager.setBackgroundScanPeriod(betweenScanPeriod);
Log.d(TAG, "Looking for beacon with minor 12345, with a scan on/off cycle of "+scanPeriod+"/"+betweenScanPeriod+" milliseconds");
Application B
long scanPeriod = 5000l;
long betweenScanPeriod = 5000l;
mBeaconManager.setBackgroundBetweenScanPeriod(scanPeriod);
mBeaconManager.setBackgroundScanPeriod(betweenScanPeriod);
Log.d(TAG, "Looking for beacon with minor 12345, with a scan on/off cycle of "+scanPeriod+"/"+betweenScanPeriod+" milliseconds");
When I ran these two apps in the background simultaneously, Application A successfully detected beacons for a straight 10 seconds, even though Application B only successfully detected beacons for a straight 5 seconds before stopping. Application B stopping scanning did not affect Application A. You can see the results yourself in the log output below. (Note Application A has process id 15841 and Application B has process id 15910).
While these tests were performed on a Moto G, I doubt they would have any different result on a Moto X, since the Moto X is just a version of the same device with higher-end hardware. I therefore suspect the issue you are seeing may be an application-specific issue. One other thing to note is that both the Moto X and Moto G have a hardware problem where Bluetooth and WiFi do not work properly simultaneously. If you are using WiFi at the same time as scanning for beacons, do not be surprised if it blocks detections.
10-07 13:29:05.949 D/BeaconReferenceApplication(15841): Looking for beacon with minor 12345, with a scan on/off cycle of 10000/10000 milliseconds
10-07 13:29:09.071 D/BeaconReferenceApplication(15910): Looking for beacon with minor 12345, with a scan on/off cycle of 5000/5000 milliseconds
...
10-07 13:29:15.582 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:16.119 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:16.738 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:16.942 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.072 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.250 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.372 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.375 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.660 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:17.660 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.075 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.080 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.289 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.297 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.501 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.513 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.820 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:18.822 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.035 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.040 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.438 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.441 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.540 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.542 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.643 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:19.644 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:20.699 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:20.910 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.125 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.239 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.344 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.462 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.751 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:21.969 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:22.170 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:23.016 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:23.129 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:23.340 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:23.444 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:23.654 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:24.180 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:24.818 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:25.012 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:25.113 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:25.245 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:25.424 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:25.527 D/BeaconService(15841): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345
10-07 13:29:26.353 D/BeaconService(15910): beacon detected :id1: e2c56db5-dffb-48d2-b060-d0f5a71096e0 id2: 1 id3: 12345