catalina: emacs, python and keyboard input (using psychopy)

Question

i'm facing the following problem.

I use python with emacs on a mac with Catalina OS.

I try to get input from the keyboard in my python script (trhough psychopy library). It does not work, and i receive the following message:

HIDBuildMultiDeviceList: Couldn’t open IOHIDManager.PsychHID-ERROR: Could not enumerate and attach to all HID devices (HIDBuildDeviceList(0,0) failed)! PsychHID-ERROR: One reason could be that some HID devices are already exclusively claimed by some 3rd party device drivers

I have a similar problem when i try to access the microphone. However, it works from within another editor. It seems that the problem is that i'm denied access to the keyboard (and mic) when running a python script.

Any help would be most welcome.

Best

thibault

Answer 1

I was experiencing the same problem, and restarting solved it!

I had code to play audio files and wait for a key on the keyboard to be hit. This code used to work, and then when I made some changes elsewhere in the code I started for the first time to experience this problem. Using the Python debugger in Terminal (python -m pdb myPsychopyCode.py) I tracked it down to occurring in the 2nd of these lines:

from psychopy.hardware import keyboard
kb = keyboard.Keyboard() # Set up a keyboard device

The error occurred replicably, whether I ran from the whole script or used it interactively in the python debugger. My fix was simply to restart! Thereafter the error messages stopped. I don't like this fix because it means I don't know what caused it or when it might happen again.

2017 MacBook Pro, macOS Big Sur 11.4, external LG monitor, bluetooth external Magic Keyboard, bluetooth external Magic Trackpad.