No data received even though topics are not empty

Question

I am using RTABmap and having a camera on a seperate machine which sends image_rect/compressed over the WiFi to my host PC. My tree looks very standard and non-broken and every topic is not empty, they are published but when I try to run rtabmap I get this error:

[ WARN] [1553595152.413459752]: /rtabmap/rtabmapviz: Did not receive data since 5 seconds! Make sure the input topics are published ("$ rostopic hz my_topic") and the timestamps in their header are set. If topics are coming from different computers, make sure the clocks of the computers are synchronized ("ntpdate"). If topics are not published at the same rate, you could increase "queue_size" parameter (current=10).
/rtabmap/rtabmapviz subscribed to (approx sync):
   /odom,
   /duo3d/left/image_rect_relay,
   /duo3d/right/image_rect_relay,
   /duo3d/left/camera_info,
   /duo3d/right/camera_info

Why is it stating that? I have every topic that is mentioned above and running at the same 30hz rate.

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Originally posted by EdwardNur on ROS Answers with karma: 115 on 2019-03-26

Post score: 0

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Original comments

Comment by Delb on 2019-03-26:
What is the output of echo $ROS_MASTER_URI for each machine ?

Comment by EdwardNur on 2019-03-26:
@Delb on my embedded machine it is: http://HOSTPC_IP:11311/ On my host pc: http://localhost:11311

Comment by matlabbe on 2019-03-31:
Which node is publishing /odom? Are the stamps matching between odom and the image topics?

Answer 1

You need to set ROS_MASTER_URI to the ip address of the computer running roscore on both machines. For example, if you run roscore on your host pc, you should then do on your embedded machine :

export ROS_MASTER_URI=http://HOSTPC_IP:11311/

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Originally posted by Delb with karma: 3907 on 2019-03-26

This answer was ACCEPTED on the original site

Post score: 0

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Original comments

Comment by EdwardNur on 2019-03-26:
Thanks for the answer, but how then I worked before? I did not set that on my host pc and sometimes I did manage RTABMAP to work

Comment by Delb on 2019-03-26:
You mean it was working before without setting those parameters ? On which machine were you usually running roscore ?

Comment by EdwardNur on 2019-03-26:
@Delb Yes, I used the same machine