问题
I am developing an android application where I have to connect to Bluetooth device on Android 4.3.
The goal of this APP is BLE Anti-loss, it can make the buzzer beep on the remote device and I want to implement the PROXIMITY PROFILE and Find Me PROFILE.
I reference the sample of BluetoothLeGatt in Android API18 and I can scan, connect and discover the services.
I found the UUID of Immediate Alert is 0x1802, but I did not found the UUID for Find Me PROFILE and PROXIMITY PROFILE at Bluetooth Developer portal.
And if I got the UUID, how to use this UUID to make the buzzer beep on the remote device.
Does anyone have an android application sample for Immediate Alert, PROXIMITY PROFILE and Find Me PROFILE?
Or can show me how to use UUID to achieve the required functionality?
回答1:
They are two different things: RSSI and TX_POWER.
TX_POWER is a power that was used to transmit the signal.RSSI is a power of the signal measured by the receiver.
It is always true: TX_POWER >= RSSI.
(Since you can't measure power greater than it was actually transmitted)
To monitor proximity between two devices (Transmitter & Receiver, or, Peripheral & Central) you should use the following equation:
Proximity Level = TX_POWER - RSSI
The intuition behind this is as follows, the transmitter is always transmit with the same power (TX_POWER), but receiver measure RSSI differently, according to the distance (proximity), when it get closer the RSSI value is getting bigger, and when it moves away the RSSI value is getting smaller.
Good luck!
来源：https://stackoverflow.com/questions/19440707/how-to-use-the-profile-of-proximity-profile-immediate-alert-service-and-find-me