The txPower mentioned by @davidgyoung is given by the formula: RSSI = -10 n log d + A where d = distance A = txPower n = signal propagation constant RSSI = dBm In free space n = 2, but it will vary based on local geometry – for example, a wall will reduce RSSI … Read more
It seems like you forgot to write the Descriptor which tells your BLE device to go in this mode. See the code lines that deal with descriptor at http://developer.android.com/guide/topics/connectivity/bluetooth-le.html#notification Without setting this descriptor, you never receive updates to a characteristic. Calling setCharacteristicNotification is not enough. This is a common mistake. code snipped protected static final … Read more
The following code is for Swift 3 (XCode 8 Beta 6). It’s an example using the standard UUIDs for serial ports like the ones on some commercial modules. So the declarations for the service and characteristics should look like this: private let UuidSerialService = “6E400001-B5A3-F393-E0A9-E50E24DCCA9E” private let UuidTx = “6E400002-B5A3-F393-E0A9-E50E24DCCA9E” private let UuidRx = “6E400003-B5A3-F393-E0A9-E50E24DCCA9E” … Read more
I have been making some experiments to get a precise position using three beacons. Results of trilateration Unluckily, the results were very disappointing in terms of quality. There were mainly two issues: In non-controlled environments, where you can find metals, and other objects that affect the signal, the received signal strength of the beacons changes … Read more
The Android 5.0.X will only allow you to use the new API for BLE. This new API comes with a new feature, which you mentioned in your question: The possibility of advertising, from your own Android device, using it in Peripheral mode. However, the disadvantaged of this new feature is that it is hardware dependent. … Read more
I answered this in another thread, repeating it here. In line-of-sight (no obstacles causing change in RSSI), -6dB seems to be double the distance. If you at 1m distance read RSSI -40dB then 2m gives -46dB, 4m gives -52dB, 8m gives -58dB, 16m gives -64dB. You can not get an exact position, only a circular … Read more
I suspect everyone adding delays is just allowing the BLE system to complete the action you have asked before you submit another one. Android’s BLE system has no form of queueing. If you do BluetoothGatt g; g.writeDescriptor(a); g.writeDescriptor(b); then the first write operation will immediately be overwritten with the second one. Yes it’s really stupid … Read more
With your Bluetooth dongle plugged in, running the following command will tell you the device name and give its state: $ hciconfig The output should look something like this: hci0: Type: BR/EDR Bus: USB BD Address: 00:01:02:aa:bb:cc ACL MTU: 1021:8 SCO MTU: 64:1 DOWN RX bytes:1000 acl:0 sco:0 events:47 errors:0 TX bytes:1072 acl:0 sco:0 commands:47 … Read more
Short answer: the correct, common, and reliable scenario is to bond. Bonding means the connection is secure and the link is trusted. It means that your local device will usually find the remote device even if its address is changing. Pairing/bonding is recommended practice in Bluetooth for security and privacy reasons. Long answer: since its … Read more
So this is now handled with the new bluetoothctl tool. A gatt table can be set up using this tool as follows:- #bluetoothctl [bluetoothctl] menu gatt [bluetoothctl] register-service 0xFFFF # (Choose yes when asked if primary service) [bluetoothctl] register-characteristic 0xAAAA read # (Select a value of 1 when prompted) [bluetoothctl] register-characteristic 0xBBBB read,write # (Select … Read more