是否可以减少扫描 BLE 设备的时间？

Posted 2023-03-05

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【中文标题】是否可以减少扫描 BLE 设备的时间？【英文标题】：Is possible to reduce the time to scan BLE devices? 【发布时间】：2017-05-31 15:37:08 【问题描述】：

我有这个代码开始扫描 BLE 设备：

Log.i("timeChar", "Begin");
customBluetoothManager.scanLeDevice(true);

然后调用scanLeDevice()，管理蓝牙适配器开始BLE扫描：

public void scanLeDevice(final boolean enable) 
        mHandler = new Handler();

        if (enable) 
            // Stops scanning after a pre-defined scan period.
            mHandler.postDelayed(new Runnable() 
                @Override
                public void run() 
                    mBluetoothAdapter.stopLeScan(mLeScanCallback);
                
            , SCAN_PERIOD);

            mBluetoothAdapter.startLeScan(mLeScanCallback);
         else 
            mBluetoothAdapter.stopLeScan(mLeScanCallback);

现在，通过扫描找到的每个设备的回调：

// Device scan callback.
    private BluetoothAdapter.LeScanCallback mLeScanCallback =
            new BluetoothAdapter.LeScanCallback() 
                @Override
                public void onLeScan(final BluetoothDevice device, int rssi,
                                     byte[] scanRecord) 

                    String name = device.getName();
                    if (name != null && name.compareTo(bluetoothDeviceName) == 0) 
                            Log.i("timeChar", "Device found");
                    
                
            ;

每次我要扫描我的 BLE 设备（具有 Peripheral 角色）时，大约需要 11 秒才能检测到它...

05-31 17:32:39.139 27545-9668/app I/timeChar: Begin
05-31 17:32:50.149 27545-27545/app I/timeChar: Device found

有什么办法可以减少这个时间？

【问题讨论】：

在自我宣传时，我发现这篇关于 BLE 的文章很有趣：atmosphere.anaren.com/wiki/… 感谢您的维基！我去看看:) 此链接无效。有新链接吗？ 【参考方案1】：

BLE 扫描和设备广告是每隔一段时间完成的。如果广告之间的间隔很长，比如说一秒钟，那么 android 可能会错过它。为了从应用程序端解决这个问题：

//global ScanSettings settings;
ScanSettings.Builder settingBuilder = new ScanSettings.Builder();
settingBuilder.setScanMode(SCAN_MODE_LOW_LATENCY);
settings = settingBuilder.build();

您稍后将其传递给扫描方法

mBluetoothAdapter.getBluetoothLeScanner().startScan(null, settings, mLeScanCallback);

【讨论】：

【参考方案2】：

为此，您应该考虑：

在 BLE 信标中设置的定义间隔。为了节省电池电量，您可以定义 BLE 信标发送的每个数据包之间的时间间隔（从 100 毫秒到几秒）。因此首先检查你的信标的时间间隔是多少。

Android 操作系统中设置的时间，用于指示您已收到新数据包（回调函数）。正如 Marcin 所指出的，您可以这样做很简单：

scanSettings = new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY ).build();

【讨论】：