要解决“BLE Eddystone数据包 - RSSI、发送功率和距离”问题,您可以使用以下解决方法:
以下是一个使用noble库的Node.js示例代码片段:
const noble = require('noble');
noble.on('stateChange', function(state) {
if (state === 'poweredOn') {
noble.startScanning();
} else {
noble.stopScanning();
}
});
noble.on('discover', function(peripheral) {
if (peripheral.advertisement.serviceUuids.indexOf('feaa') !== -1) {
const rssi = peripheral.rssi;
const txPower = peripheral.advertisement.txPowerLevel;
const distance = calculateDistance(rssi, txPower);
console.log('RSSI:', rssi);
console.log('TX Power:', txPower);
console.log('Distance:', distance);
}
});
function calculateDistance(rssi, txPower) {
const ratio = rssi * 1.0 / txPower;
if (ratio < 1.0) {
return Math.pow(ratio, 10);
} else {
const distance = (0.89976) * Math.pow(ratio, 7.7095) + 0.111;
return distance;
}
}
此代码片段使用noble库监听BLE设备的状态更改和发现事件。当发现具有Eddystone服务UUID的设备时,它获取RSSI和发送功率,并使用calculateDistance函数计算距离。
以下是一个使用BluetoothLeScanner API的Java代码示例:
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
BluetoothLeScanner scanner = bluetoothAdapter.getBluetoothLeScanner();
ScanCallback scanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) {
BluetoothDevice device = result.getDevice();
int rssi = result.getRssi();
int txPower = result.getScanRecord().getTxPowerLevel();
double distance = calculateDistance(rssi, txPower);
Log.d("RSSI", String.valueOf(rssi));
Log.d("TX Power", String.valueOf(txPower));
Log.d("Distance", String.valueOf(distance));
}
};
ScanFilter scanFilter = new ScanFilter.Builder()
.setServiceUuid(ParcelUuid.fromString("0000feaa-0000-1000-8000-00805f9b34fb"))
.build();
ScanSettings scanSettings = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
.build();
scanner.startScan(Collections.singletonList(scanFilter), scanSettings, scanCallback);
// 计算距离的方法与上述Node.js示例中的calculateDistance函数相同
此代码片段使用BluetoothLeScanner API创建一个扫描回调并在扫描结果中获取RSSI和发送功率。然后,它使用calculateDistance方法计算距离。
通过以上解决方法,您可以获取BLE Eddystone数据包的RSSI、发送功率和距离信息。请注意,距离计算是基于RSSI和发送功率之间的关系,因此可能不是绝对准确,而是近似值。