How To Fix “Permission Denied” Error When Uploading Code to Arduino on Ubuntu 18.04

In this article, we will delve into the common issue faced by many Arduino enthusiasts – the “Permission Denied” error when uploading code to Arduino on Ubuntu 18.04. We will provide detailed solutions with step-by-step instructions to help you troubleshoot this problem.

Understanding the Issue

The error, which typically reads as “avrdude: ser_open(): can’t open device “/dev/ttyACM0″: Permission denied”, usually occurs when the Arduino Integrated Development Environment (IDE) doesn’t have the necessary permissions to access the serial port.

Solution 1: Checking User Group Membership

The first step towards resolving this issue is to ensure that your username is part of both the “tty” and “dialout” groups. This can be done by running the command groups in the terminal. If your username is not part of these groups, you can add it using the following commands:

sudo usermod -a -G tty $USER
sudo usermod -a -G dialout $USER

The usermod command modifies the system account files to reflect the changes that are specified on the command line. The -a option is used to add the user to the supplementary group(s) and -G option is used to specify the group(s).

After executing these commands, log out and log back in to apply the group changes. Verify that the Arduino IDE configurations are correct, with the board set to Arduino UNO and the port set to ttyACM0. Try uploading the code again.

Solution 2: Creating UDEV Rules

Another approach is to create UDEV rules that allow your user to access the Arduino device. Here’s how you can do it:

1. Create a new file in the /etc/udev/rules.d/ directory, for example, 99-arduino.rules. You can do this using the command:

sudo nano /etc/udev/rules.d/99-arduino.rules

2. Open the file and add the following line:

SUBSYSTEM=="usb", ATTRS{idVendor}=="2341", ATTRS{idProduct}=="0043", MODE="0666"

The idVendor and idProduct values correspond to the USB Vendor ID and Product ID of your Arduino board. You can find these values by running the command lsusb in the terminal.

3. Save the file and exit (Ctrl+X, then Y, then Enter).
4. Restart your computer and try uploading the code again.

Solution 3: Updating Arduino IDE

Sometimes, the issue might be with the Arduino IDE itself. In this case, updating the IDE might help:

1. Download the latest version of Arduino IDE from the official Arduino website.
2. Install the IDE by running the command sudo ./install.sh in the extracted directory.
3. Run the script arduino-linux-setup.sh with your username as an argument, for example, ./arduino-linux-setup.sh sergio.
4. Follow any instructions provided by the script, restart your computer, and check if the issue is resolved.

Solution 4: Reinstalling Arduino IDE and avrdude

Reinstalling the Arduino IDE and avrdude might also resolve the issue:

1. Uninstall the Arduino IDE installed from the Ubuntu Software Center using the command sudo apt uninstall arduino followed by sudo apt autoremove.
2. Download the latest version of Arduino IDE from the official Arduino website and follow the installation instructions provided.
3. Install the avrdude package using the command sudo apt install avrdude.
4. Add your username to the “dialout” group by running the command sudo usermod -a -G dialout $USER.
5. Restart your computer and check if the issue is resolved.

Solution 5: Adjusting Permissions in Ubuntu Software Center

If the above solutions don’t work, you can try adjusting the permissions in the Ubuntu Software Center:

1. Install the Arduino IDE from the Ubuntu Software Center.
2. Open the Ubuntu Software Center and go to the Arduino IDE page.
3. Click on “Permissions” and enable “Access usb hardware directly”.
4. Try uploading the code again.

Conclusion

The “Permission Denied” error when uploading code to Arduino on Ubuntu 18.04 can be frustrating, but it is typically due to a permissions issue and can be resolved by following the steps outlined in this article. If none of the above solutions work for you, you can try the script created by sergiomafra, which can be found at https://github.com/sergiomafra/iniarduino. This script automates the process of setting the correct permissions and reloading UDEV rules.

Remember to follow the instructions carefully and make sure you have the necessary permissions to perform the actions mentioned in the solutions. Happy coding!