Problem with COM ports, please help me understand

Using Arduino Interfacing w/ Software on the Computer
1

Hi everyone. Sorry if this is a noob question, but I'm stumped and really need some guidance. I just got an Arduino UNO R4 wifi and I'm trying to use it for the first time. The thing is, no matter what USB port I connect my Arduino to, it always shows like COM6. I cannot select any other port on the IDE (version 2.2.1). Is this supposed to work like this? If my Arduino is not on what I'm assuming is the real COM6, I get this error, get this error, even though the IDE says my Arduino is at COM6:

Cannot perform port reset: TOUCH: error during reset: opening port at 1200bps: Serial port busy
No device found on COM6
Failed uploading: uploading error: exit status 1

If I change USB ports by trial and error it eventually finds one that I can use to upload my code. However, here comes the bigger part of the problem. I want to send the sensor data my Arduino is reading to a P5.js sketch. I tried all the libraries I could find for this and they all give me a problem with ports too. They also only find COM6 no matter with USB port I'm using, but can't open it to actually get the signal.

I already tried changing the cable and I tried using another computer, but the problem always remains (on the other computer it always reads COM3). Is this normal? What am I doing wrong? I just want to read a really basic sensor, this was supposed to be a beginner-friendly project :sob:

2

Welcome to the wonderful world of windows. Try Linux, it works fine for me.

3

I only have Windows to work with so this is not an option :upside_down_face:

1 Like
4

it may be picking up the wrong driver
sometimes I have to uninstall the COM ports to make a device work

  1. open Device manager and expand Ports COM & LPT)

  2. click View > Show Hidden Devices – you get list such as
    image

  3. right click on each COM port - click Uninstal Device – click Uninstall

  4. when complete plug in your device and hopefully the COM port should appear

1 Like
5

Thank you for the suggestion! I tried, but the problem still remains

6

Hi @arthurk37

This is a known bug with the IDE 2.2.x that is being worked on in the background.

Use this workaround whenever you start a new sketch:

  1. Close the Serial Monitor by pressing the "X" on the tab

  2. In the board/port pull-down select a board and COM port OTHER than the board & port you want to use

  3. Then re-select the board & COM port you want to use.

You should now be good to go ...

It's a bit annoying, but it is an effective solution

3 Likes
7

Thank you! It looks like it's working now

8

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.