[Bug] Using a Move Hub with a Remote Control always leads to OSError: [Errno 19] ENODEV

[beezle-bug]

Discussed in https://github.com/orgs/pybricks/discussions/2001

^{Originally posted by beezle-bug January 2, 2025}
Hello,

I try to use a move hub (firmware v3.5.0) with a remote control. The initialization of the move hub and the connection to the remote control work, but while processing the pressed buttons I always encounter OSError: [Errno 19] ENODEV after a short period of time.

I can easily reproduce the problem with the following sample code:

from pybricks.hubs import MoveHub
from pybricks.pupdevices import Remote

# Initialize the move hub.
print("Initialize the move hub.")
hub = MoveHub()

# Connect to the remote.
print("Connect to the remote.")
remote = Remote()

print("Connected.")

while True:
    # Wait until a button is pressed.
    pressed = ()
    while not pressed:
        pressed = remote.buttons.pressed()

    print("Pressed:", pressed)

    # Wait until all buttons are released.
    while pressed:
        pressed = remote.buttons.pressed()

I tried three different move hubs and encountered the problem with all of them. With two city hubs and the same remote control I cannot reproduce the problem. Therefore, I assume this might be a firmware issue regarding the move hub.

[...]

---

I tried it again with fully charged batteries and also with a second remote control.

Unfortunately, in both cases the error still occurs. With the second remote control it just takes a few seconds longer, until it happens.

When the connection to the remote control is lost, it powers down automatically.

Maybe, there is a problem with the BLE communication between the move hub and the remote controls?

Are there any known differences between the move hubs and the city hubs regarding BLE?

[EDIT]

The problem seems to occur only, if the move hub is also connected to Pybricks Code in parallel. If the program is executed standalone on the move hub, the connection to the remote control seems to be stable.

I use Pybricks Code with Edge on a Mac mini (M2 pro) with macOS 15.2. With Chrome the error also occurs.

[dlech]

The problem seems to occur only, if the move hub is also connected to Pybricks Code in parallel.

This is expected. The Bluetooth chip on the BOOST Move hub is much more limited compared to other types of hubs and can't handle being connected to more than one thing at a time.

[beezle-bug]

Hello @dlech,

thank you very much for your fast response and the explanation.