Luis Ruiz's profile - activity

I am creating multiple subscribers using the same callback function as in this post, the code is here.

Basically is this:

for ( int i = 0; i<topics.size(); i++ )  
    sub[i] = n_.subscribe( topics[i], queue_size, &MyClass::callback, this );

In this case to whom is assigned queue_size? How does it work?

I would like to think that queue_size is assigned to the subscriber sub[i] and that it doesn't matter that all the subscribers use the same callback. I mean:

Is the queue_size independent of the callback function?

This is related to this solution, I think the image_view package has to be revised.

This works, but at this date 2019/Jun/09, it has not been fixed in the image_view package. In the meanwhile I use rqt_im

This works, but at this date 2019/Jun/09 its has not been fixed in the image_view package. In the meanwhile I use rqt_im

This works, but at this date 2019/Jun/09 its has not been fixed in the image_view package. In the meanwhile I use rqt_im

This works, but at this date 2019/Jun/09 its has not been fixed in teh image_view package. In teh meanwhile I use rqt_im

I remapped /tf to /tf_0, but I can't get rosrun tf view_frames to show me the tree for /tf_0. How to do it?

I asked here and solved the problem. I had to configure the /etc/hosts files properly.

Well, I use it on robots using ROS, so maybe someone had this issue and can guide me.

I am using a main computer to launch the ros nodes in 4 robots. These robots have odroids. I can ssh into the robots by name:

ssh odroid@odroid-machine1.local
ssh odroid@odroid-machine2.local
ssh odroid@odroid-machine3.local
ssh odroid@odroid-machine4.local

I can ssh by name to all the robots except 1 odroid@odroid-machine4.local. To that one I need to ssh by ip address but I need to ssh by name to launch the nodes on it.

The network is done with a router, and something funny is happening. If I do not connect the router to internet I cannot ssh odroid-machine4.local by name, only by ip address. If a connect the router to internet everything is fine. The thing is that for some of my experiments I need to move to a place where I do not have internet access.

I think I might have some configuration problems but I do not know how to debug them.

Today I reinstalled Ubuntu from zero on odroid-machine4.local. Then I reinstalled all the software and configured the network as I always do for all the robots. I was able to ssh odroid-machine4.local by name. Then I connected all the robots to the network and again odroid-machine4.local was not recognized by name. It was until I connected the router to internet that I was able to ssh by name.

I even tried with a different router and I have the same problem.

I think I need to configure something but I don't know what.

I am using an Odroid U3 with my robot, Ubuntu 14.04. I am using an external computer to launch the ROS node of the robot.

I was wondering if there is a way to start ROS in the robot after the Odroid starts up. Like if the robot were turned on with the ROS node running after the startup. That way I would not have to use the external computer. Right now I do not need to monitor the robot so it is OK if I do not have a roscore running externally.

If I use a code snippet from ros answers, then, should my program be at least CC licensed?

What if I use an url link to the answer as a comment inside my code?

I have a group of robots. I start the programs from a "master" computer. In that computer I set up the machine names and then from a main launch file I decide with programs to run in which robot/machine, everything works.

<machine name="robot_1" address="..." user=".." env-loader="..." />

Now, I am debugging one of the programs independently, so there is no need to assign machine names. Usually I am calling several launch files, and in the launch files I run nodes like this:

<node machine="$(arg machine_name)" name="node_name" pkg="pkg_name" type="node_name" >
       ... setup ...
</node>

If I do not set up the machine name beforehand, ROS trows an error. So, is there a way to run in "this machine" without assigning a machine name? I mean, without having to change the launch files or running the configuration script to assign a machine name.

The program I am want to debug is not in the same package as the configuration file so with this I would not have to make changes in the launch files every time I want to debug.

I am running 4 robots in a network. I was wondering if it is possible to select/configure if a published topic is available for all the robots in the network or only for itself. Right now when I run the programs all the topics are available for everyone in the network.

A robot is processing an image and at the same time it is sending information through the network, I think it makes no sense to publish the image topics on the network.

In other words if a topic is not needed on the network, does it get published on the network?

This question is related.