如何使用蓝牙Le从Mi Band获取心率

Question

我想通过蓝牙从我的Mi Band 2获取心率。我试图遵循Getting Started with Bluetooth Low Energy中的示例，但我没有成功从心率中写入值。我想我错过了一些东西，但我无法意识到是什么。这是我第一次使用蓝牙和智能手环。我希望你能帮助我。我不知道我是否应该使用心率传感器作为{0x01} byte。

因此，按照示例，我下载了蓝牙LeDemo应用程序，然后从那里获得了BleWrapperBleDefinedUUIDs和BleNamesResolver。我有 2 个按钮扫描并停止。我创建了一个名为mBleWrapper的BleWrapper，用于开始扫描和停止扫描。

mBleWrapper = new BleWrapper(this, new BleWrapperUiCallbacks.Null(){

@Override
public void uiDeviceConnected(BluetoothGatt gatt, BluetoothDevice device) {
super.uiDeviceConnected(gatt, device);
}
@Override
public void uiDeviceDisconnected(BluetoothGatt gatt, BluetoothDevice device) {
super.uiDeviceDisconnected(gatt, device);
}
@Override
public void uiAvailableServices(BluetoothGatt gatt, BluetoothDevice device, List<BluetoothGattService> services) {
super.uiAvailableServices(gatt, device, services);
BluetoothGattCharacteristic c=null;
for(BluetoothGattService service : services) {
String serviceName = BleNamesResolver.resolveUuid(service.getUuid().toString());
Log.i("SERVIDE", serviceName);
}
}
c=gatt.getService(BleDefinedUUIDs.Service.HEART_RATE).getCharacteristic(BleDefinedUUIDs.Characteristic.HEART_RATE_MEASUREMENT);
mBleWrapper.writeDataToCharacteristic(c, new byte[]{0x01});
mState = mSensorState.ACC_ENABLE;
}
@Override
public void uiCharacteristicForService(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, List<BluetoothGattCharacteristic> chars) {
super.uiCharacteristicForService(gatt, device, service, chars);
}
@Override
public void uiCharacteristicsDetails(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, BluetoothGattCharacteristic characteristic) {
super.uiCharacteristicsDetails(gatt, device, service, characteristic);
}
@Override
public void uiNewValueForCharacteristic(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, BluetoothGattCharacteristic ch, String strValue, int intValue, byte[] rawValue, String timestamp) {
super.uiNewValueForCharacteristic(gatt, device, service, ch, strValue, intValue, rawValue, timestamp);
switch (mState) {
case ACC_READ:
Log.i("READ", "heart rate dta");
}
Log.i("Value", "Val" + intValue);
}
@Override
public void uiGotNotification(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, BluetoothGattCharacteristic characteristic) {
super.uiGotNotification(gatt, device, service, characteristic);
String ch = BleNamesResolver.resolveCharacteristicName(characteristic.getUuid().toString());
Log.d("AAA",  "uiGotNotification: " + ch);
}
@Override
public void uiSuccessfulWrite(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, BluetoothGattCharacteristic ch, String description) {
super.uiSuccessfulWrite(gatt, device, service, ch, description);
BluetoothGattCharacteristic c;
switch (mState) {
case ACC_ENABLE:
Log.i("ENABLED", "Heart Rate enabled");
c = gatt.getService(BleDefinedUUIDs.Service.HEART_RATE).getCharacteristic(BleDefinedUUIDs.Characteristic.HEART_RATE_MEASUREMENT);
mBleWrapper.requestCharacteristicValue(c);
mState = mSensorState.ACC_READ;
break;
case ACC_READ:
Log.i("WRITE", "SUCCESSfule write");
break;
}
}
@Override
public void uiFailedWrite(BluetoothGatt gatt, BluetoothDevice device, BluetoothGattService service, BluetoothGattCharacteristic ch, String description) {
super.uiFailedWrite(gatt, device, service, ch, description);
switch (mState) {
case ACC_ENABLE:
Log.i("FAILED", "Feailed to enbale Heart Rate");
}
}
@Override
public void uiNewRssiAvailable(BluetoothGatt gatt, BluetoothDevice device, int rssi) {
super.uiNewRssiAvailable(gatt, device, rssi);
}
@Override
public void uiDeviceFound(BluetoothDevice device, int rssi, byte[] record) {
super.uiDeviceFound(device, rssi, record);
String msg = "uiDeviceFound: "+device.getAddress()+","+device.getName();
if(devicesList.contains(device)==false) {
Log.i("Devicce", "deviceFound: " + msg);
devicesList.add(device);
genericListAdapter.notifyDataSetChanged();
}
}
});

我显示找到的所有带有ListView的设备，onClick我想连接到该项目并在日志中写入心率。

deviceListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
BluetoothGatt gatt;
BluetoothGattCharacteristic c;
connectDevice((BluetoothDevice) parent.getItemAtPosition(position));
Log.i("Read", "Get Heart Rate");
if(mBleWrapper.isConnected()==false){
Log.i("not connected", "NOT CONNECTE");
return;
}
gatt = mBleWrapper.getGatt();
c = gatt.getService(BleDefinedUUIDs.Service.HEART_RATE).getCharacteristic(BleDefinedUUIDs.Characteristic.HEART_RATE_MEASUREMENT);
mBleWrapper.requestCharacteristicValue(c);
mState=mSensorState.ACC_READ;

}
});

我还在BleWrapper类中添加了onDescpritorWriter

@Override
public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
super.onDescriptorWrite(gatt, descriptor, status);
String deviceName = gatt.getDevice().getName();
String serviceName = BleNamesResolver.resolveServiceName(descriptor.getCharacteristic().getService().getUuid().toString().toLowerCase(Locale.getDefault()));
String charName = BleNamesResolver.resolveCharacteristicName(descriptor.getCharacteristic().getUuid().toString().toLowerCase(Locale.getDefault()));
String description = "Device: " + deviceName + " Service: " + serviceName + " Characteristic: " + charName;
if(status == BluetoothGatt.GATT_SUCCESS) {
mUiCallback.uiSuccessfulWrite(mBluetoothGatt, mBluetoothDevice, mBluetoothSelectedService, descriptor.getCharacteristic(), description);
}
else {
mUiCallback.uiFailedWrite(mBluetoothGatt, mBluetoothDevice, mBluetoothSelectedService, descriptor.getCharacteristic(), description + " STATUS = " + status);
}
}

对于我使用的用于服务的 UUIDS

UUID HEART_RATE = UUID.fromString("0000180d-0000-1000-8000-00805f9b34fb");

和字符学

UUID HEART_RATE_MEASUREMENT   = UUID.fromString("00002a37-0000-1000-8000-00805f9b34fb");

在其他例子中，我看到他们也使用 UUID 作为描述符，但我没有。我知道这是一个很长的帖子和问题，但请我真的需要一些帮助。

Answer 1

有一些东西你可以检查一下。

显然，您已经成功发现了周围的设备。根据这个(蓝牙官方文档)心率服务(UUID：180d)需要先将通知设置为TRUE。像这样：

1. 使用 UUID：00002902-0000-1000-8000-00805f9b34fb 获取特征的描述符。

BluetoothGattDescriptor descriptor = gattCharacteristic.getDescriptor(Client_Characteristic_Configuration);

2. 将描述符的功能(通知)设置为 TRUE：

descriptor.setValue((BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE));

3. 将值写入 BLE 设备(使用回调函数中的 Gatt 对象)

gatt.writeDescriptor(descriptor);

在上面之后，您可以在覆盖功能中获取数据：

public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status)

通过这种方式：

BluetoothGattCharacteristic Char = gatt.getService(FORA_SERVICE_UUID).getCharacteristic(The uuid you want to connect);
byte[] data = Char.getValue();

也许您可以显示示例链接。可以更清楚地了解您使用了什么。