As of Android 8.1, unfiltered bluetooth scans are blocked when the screen is turned off. While it is surprising for such a dramatic change to be made in a minor release of Android, this is certainly an intended change based on the comments in the commit: Stop unfiltered BLE scans when the screen goes off. … Read more
Google made Android more strict by adding the new BLUETOOTH_CONNECT and BLUETOOTH_SCAN permissions. You will get SecurityException in runtime if you attempt to access any BLE API that requires these permissions. So we need to check the permissions in the activity which is set to android.intent.action.MAIN in the manifest file. I call that as MainActivity. … Read more
iOS 7 has a new options parameter in the create of CBCentralManager to turn this off, named CBCentralManagerOptionShowPowerAlertKey I’d love a solution for earlier iOS.
Long story short, YES you can use the UUID to reconnect to the same device even after you close the application (in exactly the way you say). I assume however, that you are not actually pairing with peripheral. That’s a big problem right there. You need to actually establish the pairing request and get the … Read more
A search of the Android Bluetooth Firmware source shows the following: Max concurrent active synchronous connections (BTA_GATTC_CONN_MAX): 4 on Android 4.3 7 on Android 4.4+ Max concurrent active notifications (BTA_GATTC_NOTIF_REG_MAX): 4 on Android 4.3 7 on Android 4.4 15 on Android 5.0+ As a comparison my experience with iOS is that 8 devices can be … Read more
Specification is always right ! In Bluetooth 4.0, BLE was introduced with a maximum payload of 33 bytes (not including Access Address and CRC fields). Each layer in the protocol stack takes its cut: 2 bytes for packet header (type and length), 4 bytes for MIC (when encryption is enabled), 4 bytes for L2CAP header … Read more
Unfortunately, the official answer from Google is no, the Nexus 5 no longer supports advertising. We introduced BLE peripheral mode in Android 5.0 Lollipop. Nexus 6 and Nexus 9 are the first two production Nexus devices that support BLE peripheral mode. Due to hardware chipset dependency, older Nexus devices (4/5/7) will not have access to … Read more
Pseudocode: Use a FIFO Queue or Priority Queue depends upon your business logic insert all the characteristics you want to read call your requestCharacteristics method so that it can start consuming your Queue from your onCharacteristicsRead call see if the size of the queue is greater than Zero requests one more.. be sure to peek() … Read more
The experience of Matthew Griffin matches mine. However – when we can measure for a fair period of time two things have helped us calibrate this better. We did have to wrap a simple (kalman) filter on the antenna orientation and the IMU to get a rough running commentary though – and this is not … Read more
Samsung recently published a “migration”-document on the same page I linked in my question. They exactly answer my question while comparing the new native BLE API with the Samsung BLE API: The synchronous nature of the stack and F/W hasn’t been affected. That is, if we call for example, writeCharacteristic for a particular characteristic, if … Read more