Error opening LED device

Hello,

I am trying to get started with ROSberry and Simulink. I was able to complete tutorial: Getting Started with Robot Operating System (ROS) on Raspberry Pi®, so that I was able to trigger led0 of Raspberry Pi via topic over ROS network.

However, I can't run the node as standalone node from ssh+rosrun etc etc.

I get an error: "Error opening LED device file led0." and the node can't start.

If I start the node via MATLAB "runROSNode" everything works like a charm.

Please help,

for me is very important to be able to start standalone ROS nodes from Pi board

[MathWorks Robotics and Autonomous Systems Team]

Sorry for the delay in responding, seems you are using a function which is not provided by MathWorks.

As we have "runNode"

https://www.mathworks.com/help/robotics/ref/runnode.html#bvf4xb6-7

Please confirm your workflow, and if needed please email the issue with proper steps to [e-mail]

[Stefano Dalla Gasperina]

The problem was not due to runROSNode function, but I could not launch the compiled file from ssh directly from Raspberry's terminal.

Answer 1

[Simon Ellwanger]

on your raspberry check with

rostopic list

if your topic /led is in the ROS subscription list. If so, you will see

/led

that's why you cannot start it again. It's alreaedy running and should work. Try

rostopic echo /led

to see if your raspberry can receive from /led topic.