Multiple joysticks on the same topic don't work about ros-mobile-android HOT 6 CLOSED

Oh, I guess you're right. I haven't considered controlling multiple joystick at once, so in my case the simplification works just fine. I have already implemented it this way withou issues. But yes, If I wanted to use more joysticks at once your solution is better.

from ros-mobile-android.

Yep, thats a big problem. Just to explain this:
Each Joystick widget create its own publisher. If two of them use the same topic name, one of them discards the other. It's only possible with ROS2 but there is also some kind of priority involved..

You could for example create an additional node which combines all the latest values from your 3 topics into one Twist message.

from ros-mobile-android.

Okay, this would be one of the simplest solution I came up with:

#! /usr/bin/env python

import rospy
from geometry_msgs.msg import Twist


def msgCallback(inputMsg: Twist):
    if inputMsg.linear.x:
        outputMsg.linear.x = inputMsg.linear.x

    if inputMsg.linear.y:
        outputMsg.linear.y = inputMsg.linear.y

    if inputMsg.linear.z:
        outputMsg.linear.z = inputMsg.linear.z

    if inputMsg.angular.x:
        outputMsg.angular.x = inputMsg.angular.x

    if inputMsg.angular.y:
        outputMsg.angular.y = inputMsg.angular.y

    if inputMsg.angular.z:
        outputMsg.angular.z = inputMsg.angular.z

    publisher.publish(outputMsg)


if __name__ == "__main__":
    outputMsg = Twist()

    rospy.init_node('combiner', anonymous=True)

    subscriber1 = rospy.Subscriber("/twistX", Twist, msgCallback)
    subscriber2 = rospy.Subscriber("/twistY", Twist, msgCallback)
    subscriber3 = rospy.Subscriber("/twistZ", Twist, msgCallback)
    publisher = rospy.Publisher("/twist", Twist, queue_size=10)

    rospy.spin()

Please dont judge me on that... :D

So basically this node subscribes to all of your three joystick topics, which you have to change, and republish the combination via another topic (here "/twist", but of cause you can name however you like).

from ros-mobile-android.

Thanks, I will use the workaround.
I didn't realize multiple publishers on the same topic will be overriding each other.

Edit: By the way :D The callback could be just like this

def msgCallback(msg):
    publisher.publish(msg)

from ros-mobile-android.

Regarding your edit:
I think you are not right, because only the values of the individual topics have to be copied to the tmp message if their not zero. Otherwise, you wouldnt get any benefits besides three times the message amount and a lot of zeros ^^

from ros-mobile-android.

I hope I was able to help you. I will close the issue, but feel free to open it again if you continue to have problems with that :)

from ros-mobile-android.