ROS Serial USB

1

I have had the core2 for about a year now, but haven’t done much with it yet. I have followed the tutorials and most with full success. However, I am getting stuck with other tutorial #6 using core2 to publish topics through USB.

There is how to write the code ‘battery voltage’
then there is the explanation and at the bottom it reads that we can use the Cloud IDE to flash this code. I get to that part, flash it and all seems well until I go connect.

The usb cable is connected from the micro usb to a USB port on the tinkerboard, but the reads are failing. I can see them connected, in ROStopics I see a diagnostic topic show when I run:
“rosrun rosserial_python serial_node.py _baud:=500000 _port:=/dev/ttyUSB0”

[INFO] [1553616196.792824]: ROS Serial Python Node
[INFO] [1553616196.813454]: Connecting to /dev/ttyUSB0 at 500000 baud
[ERROR] [1553616196.830286]: Error opening serial: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: ‘/dev/ttyUSB0’

I have tried changing the USB port numbers, I have also tried using ttyS1… and this is the message I get…

[WARN] [1553615473.655864]: Serial Port read failure: device reports readiness to read but returned no data (device disconnected or multiple access on port?)
[ERROR] [1553615475.395820]: Unable to sync with device; possible link problem or link software version mismatch such as hydro rosserial_python with groovy Arduino

The tinker board needs to see the topics so I can compute the information and send back the instructions.

Does the local serial have to be offline, but than the tutorial shows the ability to flash the battery code via the IDE.

Im sure I’m missing something, probably simple but I seem to be having trouble on this one. Other tutorials through ROS and your site have gone smoothly, there are a couple issues I will discuss in other topics.

Something somewhat on the same topic, is Visual Studio, based on my research there is a version for development boards, but the dependencies aren’t there, I would love to load visual studio to the tinkerboard and program from that via the usb cable when no internet is available.

2

I may have found the answers in the help Ros Tutorials 3.2 section, however that section does make note that the shield has to be disabled to make this work which I found interesting because in your tutorial it does read that it can be flashed via the IDE.

the new question becomes can I have the cloud connection and have another way to have the tinkerboard receive messages?

I will be at it again in the next couple days.

Thank you.

3

Hello Daniel,

The tutorial Using CORE2 to publish ROS topics through USB is for a case, where user want to use some other computer, e.g. laptop or workstation instead of TinkerBoard. In this use case CORE2 microUSB is connected to computer with the same cable as it would be for flashing the device.

If your use case is to run ROS on TinkerBoard, then ROS tutorials are better suitable. As far as I concern, you were successful on these, so you can just switch back to this setup.

Regards,
Łukasz