基于Python蓝牙低功耗库bleak获实时获取心率广播心率
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...")
# 根据本地名称扫描设备,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())
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