Device group access fix needed. | Generated by AI
Confirmed — here’s the current state:
/dev/ttyUSB0 exists
crw-rw---- 1 root dialout 188, 0 Jul 8 19:21 /dev/ttyUSB0
The device is present and the CH340 driver is active.
User xiaoxin is NOT yet in dialout group in this session
groups: xiaoxin adm cdrom sudo dip plugdev users lpadmin sambashare
dialout is missing — the usermod was applied previously (good), but this shell session still has the old group set. The port is currently inaccessible from this terminal.
What you need to do
Option A — quick fix in this terminal (no logout):
exec su - $USER
This starts a fresh login shell with the dialout group active. After that, verify with groups — you should see dialout in the list.
Option B — logout & login / reboot (permanent for all new terminals).
Quick test after either option
ls -l /dev/ttyUSB0 && screen /dev/ttyUSB0 9600
Or just open the Arduino IDE — it should be able to detect and connect to the port now.
Want me to run exec su - $USER for you here, or would you prefer to do it yourself?