Question on "Permission denied: '/dev/ttyUSB0'"

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1

(This is an email @geeksville received)

Python is not my native language. I was born into Basic Assemble Language and machine code. That said, here is the issue I am getting:
OS is Linux Mint
Python 3.6ish using IDLE

Meshtastic on Heltec Wireless Stick and TTGO OLED.

Traceback (most recent call last):
File “/home/dennis/.local/lib/python3.6/site-packages/serial/serialposix.py”, line 265, in open
self.fd = os.open(self.portstr, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK)
PermissionError: [Errno 13] Permission denied: ‘/dev/ttyUSB0’

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “/home/dennis/Desktop/gob.py”, line 3, in
interface=meshtastic.StreamInterface()
File “/home/dennis/.local/lib/python3.6/site-packages/meshtastic/init.py”, line 365, in init
devPath, 921600, exclusive=True, timeout=0.5)
File “/home/dennis/.local/lib/python3.6/site-packages/serial/serialutil.py”, line 240, in init
self.open()
File “/home/dennis/.local/lib/python3.6/site-packages/serial/serialposix.py”, line 268, in open
raise SerialException(msg.errno, “could not open port {}: {}”.format(self._port, msg))
serial.serialutil.SerialException: [Errno 13] could not open port /dev/ttyUSB0: [Errno 13] Permission denied: ‘/dev/ttyUSB0’

Yes…I installed PYSERIAL and uninstalled Serial.

The program is Three Line starting with Import Meshtastic. It just beacon HELLO every 60 sec for the purpose of seeing how far I can get using Meshtastic.

Note: I have written many Arduino Apps with LoRa and Ive gotton DX of 10 mile LOS.

2

Hi Dennis,

I bet it is a linux filesystem permissions thing. Can you post the results of “ls -l /dev/ttyUSB0”?

I’m kinda guessing that mint linux doesn’t have the udev rules that automatically give users besides root access to the serial ports. If that is the case you’ll want to put the attached file in /etc/init.d/udev/99-serialports-udev.rules. Then run “sudo /etc/init.d/udev restart”

re: lora experience - cool!

# Copyright (c) 2014-present PlatformIO <contact@platformio.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

#####################################################################################
#
# INSTALLATION
#
# Please visit > https://docs.platformio.org/en/latest/faq.html#platformio-udev-rules
#
#####################################################################################

#
# Boards
#

# CP210X USB UART
SUBSYSTEMS=="usb", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE:="0666"

# FT232R USB UART
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE:="0666"

# Prolific Technology, Inc. PL2303 Serial Port
SUBSYSTEMS=="usb", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", MODE:="0666"

# QinHeng Electronics HL-340 USB-Serial adapter
SUBSYSTEMS=="usb", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", MODE:="0666"

# Arduino boards
SUBSYSTEMS=="usb", ATTRS{idVendor}=="2341", ATTRS{idProduct}=="[08][02]*", MODE:="0666"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="2a03", ATTRS{idProduct}=="[08][02]*", MODE:="0666"

# Arduino SAM-BA
ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="6124", ENV{ID_MM_DEVICE_IGNORE}="1"
ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="6124", ENV{MTP_NO_PROBE}="1"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="6124", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="6124", MODE:="0666"

# Digistump boards
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="16d0", ATTRS{idProduct}=="0753", MODE:="0666", ENV{ID_MM_DEVICE_IGNORE}="1"

# STM32 discovery boards, with onboard st/linkv2
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="374?", MODE:="0666"

# Maple with DFU
SUBSYSTEMS=="usb", ATTRS{idVendor}=="1eaf", ATTRS{idProduct}=="000[34]", MODE:="0666"

# USBtiny
SUBSYSTEMS=="usb", ATTRS{idProduct}=="0c9f", ATTRS{idVendor}=="1781", MODE="0666"

# USBasp V2.0
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="05dc", MODE:="0666"

# Teensy boards
ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789]?", ENV{ID_MM_DEVICE_IGNORE}="1"
ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789]?", ENV{MTP_NO_PROBE}="1"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789]?", MODE:="0666"
KERNEL=="ttyACM*", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789]?", MODE:="0666"

#TI Stellaris Launchpad
SUBSYSTEMS=="usb", ATTRS{idVendor}=="1cbe", ATTRS{idProduct}=="00fd", MODE="0666"

#TI MSP430 Launchpad
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0451", ATTRS{idProduct}=="f432", MODE="0666"


#
# Debuggers
#

# Black Magic Probe
SUBSYSTEM=="tty", ATTRS{interface}=="Black Magic GDB Server"
SUBSYSTEM=="tty", ATTRS{interface}=="Black Magic UART Port"

# opendous and estick
ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="204f", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Original FT232/FT245 VID:PID
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Original FT2232 VID:PID
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Original FT4232 VID:PID
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6011", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Original FT232H VID:PID
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6014", MODE="660", GROUP="plugdev", TAG+="uaccess"

# DISTORTEC JTAG-lock-pick Tiny 2
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="8220", MODE="660", GROUP="plugdev", TAG+="uaccess"

# TUMPA, TUMPA Lite
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="8a98", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="8a99", MODE="660", GROUP="plugdev", TAG+="uaccess"

# XDS100v2
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="a6d0", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Xverve Signalyzer Tool (DT-USB-ST), Signalyzer LITE (DT-USB-SLITE)
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bca0", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bca1", MODE="660", GROUP="plugdev", TAG+="uaccess"

# TI/Luminary Stellaris Evaluation Board FTDI (several)
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bcd9", MODE="660", GROUP="plugdev", TAG+="uaccess"

# TI/Luminary Stellaris In-Circuit Debug Interface FTDI (ICDI) Board
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bcda", MODE="660", GROUP="plugdev", TAG+="uaccess"

# egnite Turtelizer 2
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="bdc8", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Section5 ICEbear
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="c140", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="c141", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Amontec JTAGkey and JTAGkey-tiny
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="cff8", MODE="660", GROUP="plugdev", TAG+="uaccess"

# TI ICDI
ATTRS{idVendor}=="0451", ATTRS{idProduct}=="c32a", MODE="660", GROUP="plugdev", TAG+="uaccess"

# STLink v1
ATTRS{idVendor}=="0483", ATTRS{idProduct}=="3744", MODE="660", GROUP="plugdev", TAG+="uaccess"

# STLink v2
ATTRS{idVendor}=="0483", ATTRS{idProduct}=="3748", MODE="660", GROUP="plugdev", TAG+="uaccess"

# STLink v2-1
ATTRS{idVendor}=="0483", ATTRS{idProduct}=="374b", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Hilscher NXHX Boards
ATTRS{idVendor}=="0640", ATTRS{idProduct}=="0028", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Hitex STR9-comStick
ATTRS{idVendor}=="0640", ATTRS{idProduct}=="002c", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Hitex STM32-PerformanceStick
ATTRS{idVendor}=="0640", ATTRS{idProduct}=="002d", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Altera USB Blaster
ATTRS{idVendor}=="09fb", ATTRS{idProduct}=="6001", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Amontec JTAGkey-HiSpeed
ATTRS{idVendor}=="0fbb", ATTRS{idProduct}=="1000", MODE="660", GROUP="plugdev", TAG+="uaccess"

# SEGGER J-Link
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0101", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0102", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0103", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0104", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0105", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0107", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="0108", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1010", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1011", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1012", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1013", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1014", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1015", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1016", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1017", MODE="660", GROUP="plugdev", TAG+="uaccess"
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1018", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Raisonance RLink
ATTRS{idVendor}=="138e", ATTRS{idProduct}=="9000", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Debug Board for Neo1973
ATTRS{idVendor}=="1457", ATTRS{idProduct}=="5118", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Olimex ARM-USB-OCD
ATTRS{idVendor}=="15ba", ATTRS{idProduct}=="0003", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Olimex ARM-USB-OCD-TINY
ATTRS{idVendor}=="15ba", ATTRS{idProduct}=="0004", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Olimex ARM-JTAG-EW
ATTRS{idVendor}=="15ba", ATTRS{idProduct}=="001e", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Olimex ARM-USB-OCD-TINY-H
ATTRS{idVendor}=="15ba", ATTRS{idProduct}=="002a", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Olimex ARM-USB-OCD-H
ATTRS{idVendor}=="15ba", ATTRS{idProduct}=="002b", MODE="660", GROUP="plugdev", TAG+="uaccess"

# USBprog with OpenOCD firmware
ATTRS{idVendor}=="1781", ATTRS{idProduct}=="0c63", MODE="660", GROUP="plugdev", TAG+="uaccess"

# TI/Luminary Stellaris In-Circuit Debug Interface (ICDI) Board
ATTRS{idVendor}=="1cbe", ATTRS{idProduct}=="00fd", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Marvell Sheevaplug
ATTRS{idVendor}=="9e88", ATTRS{idProduct}=="9e8f", MODE="660", GROUP="plugdev", TAG+="uaccess"

# Keil Software, Inc. ULink
ATTRS{idVendor}=="c251", ATTRS{idProduct}=="2710", MODE="660", GROUP="plugdev", TAG+="uaccess"

# CMSIS-DAP compatible adapters
ATTRS{product}=="*CMSIS-DAP*", MODE="660", GROUP="plugdev", TAG+="uaccess"

#SEGGER J-LIK
ATTR{idProduct}=="1001", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1002", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1003", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1004", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1005", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1006", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1007", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1008", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1009", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100a", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100b", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100c", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100d", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100e", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="100f", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1010", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1011", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1012", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1013", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1014", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1015", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1016", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1017", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1018", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1019", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101a", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101b", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101c", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101d", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101e", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="101f", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1020", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1021", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1022", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1023", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1024", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1025", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1026", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1027", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1028", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="1029", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102a", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102b", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102c", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102d", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102e", ATTR{idVendor}=="1366", MODE="666"
ATTR{idProduct}=="102f", ATTR{idVendor}=="1366", MODE="666"
3

I think the dialout group is in Linux Mint as well as most forms of Debian, maybe other distros too.
Your user can be added to allow access with:

sudo usermod -a -G dialout <username>  # To allow access to the /dev/ttyUSB#
2 Likes
4

This required a system reboot for me on Ubuntu - not even a log out / in worked

1 Like
5

Edit: how embarrassing, proper reading could save lives :wink:

FYI: Logging out and back in should also work.

6

I had this issue when trying to connect to a heltec Lora from a Raspberry Pi. Two things solved my issue

(Step 1 probably not the best method and needs to be done with every reboot)

  1. sudo chmod 766 /dev/ttyUSB0

  2. Physically press the user button on the heltec to “wake” the device before trying to run the python script

Notes:

Chmod owner

  • Owner can read
  • Owner can write
  • Owner can execute

Chmod group

  • Group can read
  • Group can write
  • Group can’t execute

Chmod other

  • Others can read
  • Others can write
  • Others can’t execute
1 Like
7

Hi, @mauricecyril. Thanks, I’ll add this to the readme, I think the ideal fix is what @ryan55555 mentioned.

sudo usermod -a -G dialout

2 Likes
8
9

Thanks Kevin. Amazing project btw! Thanks to you and all the contributors.

1 Like