Arduino zero rosserial

Using Arduino Interfacing w/ Software on the Computer
1

Hi

I have an arduino zero, connected to native port, Arduino IDE 1.8.7, Ubuntu 18.04 and ROS melodic.

I did the rossserial arduino tutorial Hello World, to publish something to a ros topic. link text

My commands: 1.) roscore

separate terminal 2.) rosrun rosserial_python serial_node.py _port:=/dev/ttyACM0 _baud:=57600

The command window shows this: If think I have tried nearly everything. deinstall and install it, switched the computer off and on, tried with multiple baudrates (it is not hardcode in the .ino file, since I use the file form the tutorial, checked the usb port, tried commands, #define USE_USBCON, ros::spinOnce(), tried to set the baudrate in the .ino file: nodehande.getHardware()->setBaud(57600);

Nothing works and more surprisingly if I do the same procedure with an Arduino Uno it works. They should have the same architecture?

Does someone know where the mistake could be?

Thanks