前提
心率设备需支持心率广播功能
心率广播功能需处于开启状态
心率广播功能最多只能同时连接一台设备，如有其它设备正在连接需要先断开
使用方法
安装蓝牙低功耗库break
pip install bleak
开启心率广播功能后设备界面会显示当前设备名称，将设备名称替换到变量device_name
运行程序，将自动扫描设备并连接到心率广播功能，异步获取心率数据
代码

import asyncio
from bleak import BleakClient, BleakScanner
from bleak.backends.characteristic import BleakGATTCharacteristic
 
# 设备名称
device_name: str = "HUAWEI WATCH HR-341"
# 心率
value = 0
# 最大连接超时时间
timeout = 10
 
# 通知处理器函数，当收到通知时调用
def notification_handler(characteristic: BleakGATTCharacteristic, data: bytearray):
    global value
    value = int(data.hex().split('06')[1], 16)
    print(value)
 
# 异步函数：扫描设备并根据本地名称获取地址
async def scan_for_device(device_name: str):
    devices = await BleakScanner.discover()
    for device in devices:
        if device.name == device_name:
            return device
    return None
 
# 异步函数：查找描述为“Heart Rate Measurement”的特征UUID
async def find_heart_rate_measurement_uuid(client: BleakClient):
    for service in client.services:
        for characteristic in service.characteristics:
            if "Heart Rate Measurement" in characteristic.description:
                return characteristic.uuid
    return None
 
# 异步主函数
async def main():
    print("Starting scan...")
    # 根据设备名称扫描设备，也可以直接填入设备的物理地址
    device = await scan_for_device(device_name)
 
    if device is None:
        print(f"Device with name {device_name} not found.")
        return
 
    print(f"Found device: {device.name} ({device.address})")
 
    # 创建一个事件对象，用于处理断开连接的情况
    disconnected_event = asyncio.Event()
 
    # 断开连接时的回调函数
    def disconnected_callback(client):
        print("Disconnected callback called!")
        disconnected_event.set()
 
    print("Connecting to device...")
    async with BleakClient(device, disconnected_callback=disconnected_callback, timeout=timeout) as client:
        print("Connected")
 
        # 查找“Heart Rate Measurement”特征UUID(心率广播)
        hr_measurement_uuid = await find_heart_rate_measurement_uuid(client)
        if hr_measurement_uuid:
 
            # 开始通知，并设置通知处理器
            await client.start_notify(hr_measurement_uuid, notification_handler)
            # 等待断开连接事件
            await disconnected_event.wait()
        else:
            print("Heart Rate Measurement characteristic not found.")
 
# 运行异步主函数
asyncio.run(main())

来源：https://www.cnblogs.com/qiao39gs/p/18295241/real-time-heart-rate-broadcast-with-python-bleak-ble-library