Possible to run notification on two different devices at once.

• bleak version: 0.6.4
• Python version: 3.6.5
• Operating System: OSX Catalina

Description

I’m trying to connect to some heart rate monitors and I can successfully connect to 1 and read the data properly, but I would like to connect and start notification on more than one device at the same time.

Is that possible with bleak?

What I Did

I defined an aync function connect_and_record which connects to a device using the BleakClient by UUID and starts notification with a handler that stores the data in a database.

I tried to run two devices using:

asyncio.gather(connect_and_record(uuid_1), connect_and_record(uuid_2)).

What happens is the first device connects and begins notification, and then the second device connects and it seems to cancel out the first one.

If you have any suggestions I would appreciate it. Thanks.

[kswann-imb]

Thanks @hbldh

[mabhijithn]

I would like to restart this issue again. I am unable to read notifications from two devices simultaneuously. I am running:

• bleak==0.11.0
• linux kernel 5.4.0-72-generic
• Linux Mint (Ubuntu 20.04)

The code I am running is given below based on Issue 345:

import asyncio
from bleak import BleakClient

erc1address = "80:EA:CA:70:00:01"
erc2address = "80:EA:CA:70:00:02"
read_characteristic = '16005991-b131-3396-014c-664c9867b917'

with open('file_one.csv','w') as f:
    f.write("ERC-1\n")

with open('file_two.csv','w') as f:
    f.write("ERC-2\n")

def callback_one(sender, data):
     with open('file_one.csv','a') as f:
         for i in range(len(data)):
             f.write(f'{data[i]}')
         
def callback_two(sender, data):
     with open('file_two.csv','a') as f:
         for i in range(len(data)):
             f.write(f'{data[i]}')

def run(addresses):
    loop = asyncio.get_event_loop()

    tasks = asyncio.gather(connect_one(addresses[0]) ,connect_two(addresses[1]))

    loop.run_until_complete(tasks)


async def connect_one(address):
    print("starting", address, "loop")
    async with BleakClient(address, timeout=20.0) as client:

        print("connect to", address)
        try:
            await client.start_notify(read_characteristic, callback_one)
            while 1:
                await asyncio.sleep(1)
        except Exception as e:
            if e is KeyboardInterrupt:
                await client.stop_notify(read_characteristic)

    print("disconnect from", address)

async def connect_two(address):
    print("starting", address, "loop")
    async with BleakClient(address, timeout=20.0) as client:
        print("connect to", address)
        try:
            await client.start_notify(read_characteristic, callback_two)
            while 1:
                await asyncio.sleep(1)
        except Exception as e:
            if e is KeyboardInterrupt:
                await client.stop_notify(read_characteristic)

    print("disconnect from", address)

if __name__ == "__main__":
    run(
        [erc1address, erc2address]
    )

I have while 1: await sleep(1) because I need to read notifications from both devices. If I replace that with just await sleep(10) for instance, then after 10 seconds, the second connected device notifications are read. However, my devices send notifications continuously, therefore I need to read data from both.

It would be great if any suggestions/help can be provided.