Issue sending triggers with Cedrus C-pod


I am trying to send send out triggers (int value ‘1’) via a Cedrus C-pod. Initially, my script (attached, made in the builder) was working fine - no errors were thrown, the C-POD flashed to indicate a trigger was sent. So, I know that the USB drivers are up to date on my computer, and that the Pyxid library should be working fine.

All of a sudden, the code stopped working - I got the error message copied below. Any thoughts on why this could be? I think it could point to my C-pod being broken, but I’m not sure. Thanks so much for any insight.

PsychoPy Versions
This issue occurs with both PsychoPy 3.2.4 and 2020.2.4

Error Message
Traceback (most recent call last):

File “C:\Users\cmal\Documents\PsychoPy_Scripts\”, line 96, in

devices = pyxid.get_xid_devices()

File “C:\Program Files\PsychoPy3\lib\site-packages\”, line 10, in get_xid_devices

scanner = XidScanner()

File “C:\Program Files\PsychoPy3\lib\site-packages\pyxid\”, line 18, in init


File “C:\Program Files\PsychoPy3\lib\site-packages\pyxid\”, line 44, in detect_xid_devices

returnval = con.send_xid_command("_c1", 5).decode('ASCII')

UnicodeDecodeError: ‘ascii’ codec can’t decode byte 0xa1 in position 1: ordinal not in range(128)

Metronome_cpod.psyexp (14.5 KB)

Update: I have confirmed that C-POD works on my computer with superlab. Thus, the issue must lie with the PsychoPy code. Any ideas?

We are able to duplicate the issue in-house. It seems specific to Python as both SuperLab and Xidon work (they use C++). We’re looking into it.


Everything working now! Error went away on its own. Just restarted the computer.