OpenBCI GUI works in 3.3.7 but doesn't work in 4

I have an application that works in Processing 3.3.7 but not in 4. This line gets an error.

Serial port;
The error message is: “The type Serial is ambiguous”

Can someone help me with this?


Which release of processing 4 you are using ??
Some was include issues

Presently, I am using 4.1.1

Hello @hcdebey,

A little more information helps us to solve problems.

If you are using OpenBCI_GUI the github repository is here:

Read through this for recommendations on installing:

You can also search through the issues for any reported problems including the one you stated.

Issues on GitHub searching for “serial” (a broader search):

From what I gleaned perusing the GitHub page and issues:

  • Use Processing 3.5.4

If you want to use Processing 4:

  • Use the latest version v5.1.0
  • Try it with Processing 4.0b2 and then Processing 4.0b3
  • Also try Processing 4.2
  • The issue states that:

Processing 4 beta 3 uses Java 17 and JavaFX 17, whereas this PR began with Processing 4 beta 2 which uses Java 11. I hope this should be ok with forward compatibility.

What hardware are you using?

Let us know if you had success with Processing 4 and details about versions of Processing and OpenBCI_GUI.


After I went to 3.5.4 the problem went away.

Thanks for the help that people have offered.

1 Like

Hello @hcdebey,

I did get OpenBCI GUI v5.1.0 running with Processing 4.2 and as able to view the sample data:

I did not have any hardware devices to connect to.

Cool stuff!