python serial [Errno 13] Permission denied: /dev/tty*

Question

I try to open serial port, but cant with permission. But works with sudo.

How i can get permission for serial port?

sas@sas-linuxmint ~ $groups sas
sas : sas adm tty dialout cdrom sudo dip plugdev lpadmin sambashare

This my code:

def get_serial_port():
    ser_devs = [dev for dev in os.listdir('/dev') if dev.startswith('tty')]
    for i in ser_devs:
        port = "/dev/" + i
        try :
            ser = serial.Serial(port, 19200)
            if ser.is_open:
                print("OPEN!!!!!!!!!!!!!!!!!!!!!! {}".format(port))
            ser.close()
        except serial.SerialException as e:
            print(e, port)
    return None

output:

[Errno 13] could not open port /dev/ttyprintk: [Errno 13] Permission denied: '/dev/ttyprintk' /dev/ttyprintk

for all ports.

I tried change mod for port, but it doesn't work too

sudo chmod 766 /dev/ttyS10
sudo chmod -R a+rw /dev/ttyS10
sudo chmod 777 /dev/ttyS10
sudo chmod 666 /dev/ttyS10

It look like it is not python issue. Did you try to use root or sudo to execute your code? — Andy Wong
What are you trying to accomplish with this?? Not every tty is supposed to be handled by normal users, especially /dev/ttyprintk ;-) — Alfe
"Did you try to use root or sudo to execute your code?" Yes, with sudo it works. — mamol
" Not every tty is supposed to be handled by normal users, especially /dev/ttyprintk ;-)" I try for all ports /dev/tty*, /dev/ttyprintk just first from list :) — mamol

yaumera yaumera · Accepted Answer · 2021-04-04T10:07:00

may be 2 years late but, you simply add your user to the tty group eg:

sudo usermod -a -G tty $USER

link

python serial [Errno 13] Permission denied: /dev/tty*

1 Answers