蓝牙模组产品概览

BLE 技术基础

BLE（Bluetooth Low Energy，低功耗蓝牙）是蓝牙 4.0 引入的低功耗版本，专为 IoT 设计。

BLE vs 经典蓝牙

特性	经典蓝牙（BR/EDR）	BLE
速率	1-3Mbps	125kbps-2Mbps
功耗	高（1W）	极低（1mW）
延迟	100ms	6ms
覆盖	10-100m	10-400m
主要用途	音频、文件传输	IoT 传感器、可穿戴
配对时间	慢（秒级）	快（毫秒级）

BLE 5.x 新特性

版本	新增特性	关键改进
BLE 5.0	2× 速率、4× 覆盖、8× 广播容量	长距离模式（125kbps，+20dB）
BLE 5.1	方向查找（AoA/AoD）	厘米级室内定位
BLE 5.2	LE Audio、EATT	低功耗音频、多流传输
BLE 5.3	增强连接更新	更低功耗
BLE 5.4	广播加密	安全性提升

移远 BLE 产品

移远的 BLE 模组主要以组合形式出现（BLE + 蜂窝 或 BLE + Wi-Fi）：

型号	BLE 版本	组合	芯片	特点
BG95-Mini	BLE 5.0	NB-IoT + Cat.M + BLE	高通	超小尺寸
BC660K	BLE 5.0	NB-IoT + BLE	高通	低功耗
FC41D	BLE 5.0	Wi-Fi 6 + BLE	联发科	高速组合

BLE 协议栈

GATT 架构

GATT（Generic Attribute Profile）是 BLE 数据交换的核心：

Profile（配置文件）
  └── Service（服务）
        └── Characteristic（特征值）
              ├── Value（值）
              ├── Descriptor（描述符）
              └── Properties（属性：Read/Write/Notify/Indicate）

示例：心率服务（Heart Rate Service）
  Service UUID: 0x180D
    Characteristic: Heart Rate Measurement（0x2A37）
      Properties: Notify
      Value: [心率值, RR间期...]
    Characteristic: Body Sensor Location（0x2A38）
      Properties: Read
      Value: [位置：手腕/胸部/手指...]

BLE 广播（Advertising）

BLE 广播用于设备发现和数据广播（无需连接）：

广播类型：
  ADV_IND：可连接无向广播（最常用）
  ADV_NONCONN_IND：不可连接广播（Beacon）
  ADV_DIRECT_IND：可连接定向广播
  
广播数据格式（AD Structure）：
  Length | Type | Data
  
  常用 Type：
  0x01：Flags（LE General Discoverable Mode）
  0x02/0x03：16位 UUID 列表
  0x08/0x09：设备名称（缩写/完整）
  0xFF：厂商自定义数据（iBeacon 使用此类型）
  
iBeacon 数据格式：
  公司标识：0x004C（Apple）
  类型：0x02
  长度：0x15
  UUID：16字节
  Major：2字节
  Minor：2字节
  TX Power：1字节（用于距离估算）

BLE 开发示例

Python BLE 扫描（树莓派/Linux）

import asyncio
from bleak import BleakScanner, BleakClient

async def scan_devices():
    """扫描附近 BLE 设备"""
    print("扫描 BLE 设备...")
    devices = await BleakScanner.discover(timeout=5.0)
    
    for device in devices:
        print(f"设备: {device.name or '未知'}")
        print(f"  地址: {device.address}")
        print(f"  RSSI: {device.rssi} dBm")
        print(f"  距离估算: {estimate_distance(device.rssi):.1f} m")
        print()

def estimate_distance(rssi, tx_power=-59, n=2.0):
    """基于 RSSI 估算距离（粗略）"""
    if rssi == 0:
        return -1
    ratio = rssi / tx_power
    if ratio < 1.0:
        return ratio ** 10
    else:
        return 0.89976 * (ratio ** 7.7095) + 0.111

async def read_heart_rate(device_address):
    """读取心率设备数据"""
    HEART_RATE_SERVICE = "0000180d-0000-1000-8000-00805f9b34fb"
    HEART_RATE_CHAR = "00002a37-0000-1000-8000-00805f9b34fb"
    
    async with BleakClient(device_address) as client:
        print(f"已连接: {device_address}")
        
        # 读取设备信息
        services = await client.get_services()
        
        # 订阅心率通知
        def heart_rate_handler(sender, data):
            # 解析心率数据
            flags = data[0]
            if flags & 0x01:  # 16位心率值
                heart_rate = int.from_bytes(data[1:3], 'little')
            else:  # 8位心率值
                heart_rate = data[1]
            print(f"心率: {heart_rate} bpm")
        
        await client.start_notify(HEART_RATE_CHAR, heart_rate_handler)
        await asyncio.sleep(30)  # 监听30秒
        await client.stop_notify(HEART_RATE_CHAR)

asyncio.run(scan_devices())

Android BLE 开发

// Android BLE 扫描和连接
public class BLEManager {
    private BluetoothAdapter bluetoothAdapter;
    private BluetoothLeScanner scanner;
    private BluetoothGatt gatt;
    
    // 扫描回调
    private ScanCallback scanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            BluetoothDevice device = result.getDevice();
            int rssi = result.getRssi();
            
            Log.d("BLE", "Found: " + device.getName() + 
                  " (" + device.getAddress() + ") RSSI: " + rssi);
            
            // 找到目标设备后连接
            if ("MyDevice".equals(device.getName())) {
                scanner.stopScan(scanCallback);
                connectToDevice(device);
            }
        }
    };
    
    public void startScan() {
        ScanSettings settings = new ScanSettings.Builder()
            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
            .build();
        
        scanner.startScan(null, settings, scanCallback);
    }
    
    private void connectToDevice(BluetoothDevice device) {
        gatt = device.connectGatt(context, false, new BluetoothGattCallback() {
            @Override
            public void onConnectionStateChange(BluetoothGatt gatt, 
                                                int status, int newState) {
                if (newState == BluetoothProfile.STATE_CONNECTED) {
                    Log.d("BLE", "Connected!");
                    gatt.discoverServices();
                }
            }
            
            @Override
            public void onServicesDiscovered(BluetoothGatt gatt, int status) {
                // 获取心率服务
                BluetoothGattService hrService = gatt.getService(
                    UUID.fromString("0000180d-0000-1000-8000-00805f9b34fb")
                );
                
                if (hrService != null) {
                    BluetoothGattCharacteristic hrChar = hrService.getCharacteristic(
                        UUID.fromString("00002a37-0000-1000-8000-00805f9b34fb")
                    );
                    
                    // 开启通知
                    gatt.setCharacteristicNotification(hrChar, true);
                }
            }
            
            @Override
            public void onCharacteristicChanged(BluetoothGatt gatt,
                                                BluetoothGattCharacteristic characteristic) {
                byte[] data = characteristic.getValue();
                int heartRate = data[1] & 0xFF;
                Log.d("BLE", "Heart Rate: " + heartRate + " bpm");
            }
        });
    }
}