In the Arduino IDE on my RPi on the top there is a header that says, File, Edit, Tools and help.

Following a Magpi article it said to go to tools then serial port and change that depending on what board you use. The only problem is that it's not there, when I click tools I scroll down and there grayed out it says, serial port.

Why is this grayed out? And why can I not change it? Also, what port should be used for an Uno?

2 Answers 2


It's greyed out because it can't find any serial ports.

That could be because:

  • There aren't any detected (not got the right kernel modules loaded)
  • You don't have permission to access the serial ports (are you in the dialout group?)

Have you followed the Linux installation instructions? http://playground.arduino.cc/Linux/All


That would require RTFM :)

For the last many years (on various linux variants including rpi) a quick solution is:

sudo chmod ugo+rw /dev/ttyACM0

after plugging in the arduino.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.