and Arduino connection

I’m brand new here in this forum and also in using processing.
So first: English is not my first language. Sorry for any mistakes or misunderstandings.

I’ve got the following problem while trying to use an Arduino Uno with processing:
My OS is Windows 10, the Arduino is connected via USB to COM1 and running the Standard Firmata, I#M using the processing IDE in Python mode.
I am not able to connect to the Arduino in Python mode. An example:

in Java mode:

   import processing.serial.*;

   Serial myPort;  // Create object from Serial class
   int val;           // Data received from the serial port

   void setup()
     size(200, 200);
     myPort = new Serial(this, "COM1", 57600);

   void draw()

that works fine.

Now in Python mode:


   def setup():
       a = Arduino(this, "COM1", 57600)

   def draw():

ends with a mistake:

UnsatisfiedLinkError: jssc.SerialNativeInterface.openPort(Ljava/lang/String;Z)J
at jssc.SerialNativeInterface.openPort(Native Method)
at jssc.SerialPort.openPort(
at processing.serial.Serial.(Unknown Source)
at processing.serial.Serial.(Unknown Source)
at cc.arduino.Arduino.(

and so on.

What is wrong here? I think it is a problem with the serial library in Python mode.
Can anybody help me?

1 Like

“… Deleting windows32\jSSC-2.8.dll works perfectly …”


Thank you very much, tabreturn.
Great, it works.
It was a little bit tricky because I didn’t know exactly what was meant and what I should do.
The path to find the .dll was c:\programs (x86)\processing-3.5.4\modes\java\libraries\serial\library\windows32 and it was difficult for a beginner to find that. :innocent: :innocent:
After deleting the .dll everything works fine.


Yeah! This is terrible for beginners, It bothers me so much!
From time to time I try to find someone with skills to fix this :confused:

I’m glad you made it work! Now see if you can play with some potentiometers!

1 Like

I have a fix in for this. I believe it’s in build 3058. I can only test Windows in a VM, so please let me know if you continue to see it.


Wow! That is great news I don’t have access to Windows right now, but I’ll have a look ASAP!


Thank you so much, @mpsftw !

That’s correct – currently if you install Python mode from Processing PDE you will see a 3058+ build including that Windows fix. I just tried, and PDE installed 3059.

1 Like