temp_sensor_aioble.py

# 本作品采用MIT许可证授权。
# 版权所有 (c) 2013-2023 OpenMV LLC。保留所有权利。
# https://github.com/openmv/openmv/blob/master/LICENSE
#
from micropython import const

import asyncio
import aioble
import bluetooth

import random
import struct

# org.bluetooth.service.environmental_sensing
_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
# org.bluetooth.characteristic.temperature
_ENV_SENSE_TEMP_UUID = bluetooth.UUID(0x2A6E)
# org.bluetooth.characteristic.gap.appearance.xml
_ADV_APPEARANCE_GENERIC_THERMOMETER = const(768)

# 发送广播信标的频率。
_ADV_INTERVAL_MS = 250_000

# 注册GATT服务器。
temp_service = aioble.Service(_ENV_SENSE_UUID)
temp_characteristic = aioble.Characteristic(
    temp_service, _ENV_SENSE_TEMP_UUID, read=True, notify=True
)
aioble.register_services(temp_service)


# 用于编码温度特征值的辅助函数（sint16，单位为百分之一度）。
def _encode_temperature(temp_deg_c):
    return struct.pack("<h", int(temp_deg_c * 100))


# 这里相当于周期性地轮询硬件传感器。
async def sensor_task():
    t = 24.5
    while True:
        temp_characteristic.write(_encode_temperature(t))
        t += random.uniform(-0.5, 0.5)
        await asyncio.sleep_ms(1000)


# 依次等待连接。当有中心设备连接时
# 不进行广播。
async def peripheral_task():
    while True:
        async with await aioble.advertise(
            _ADV_INTERVAL_MS,
            name="mpy-temp",
            services=[_ENV_SENSE_UUID],
            appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER,
        ) as connection:
            print("Connection from", connection.device)
            await connection.disconnected()


# 运行两个任务。
async def main():
    t1 = asyncio.create_task(sensor_task())
    t2 = asyncio.create_task(peripheral_task())
    await asyncio.gather(t1, t2)


asyncio.run(main())