ros-raspbot-v2/troubleshooting.md

Troubleshooting

No sensor data is received on topic

Data is sent over UDP, and if the sensor data exceeds the maximum receive buffer size of the network stack, the data frame will be silently discarded.

The solution is to increase the receive memory buffer size

sudo sysctl -w net.core.rmem_max=2097152
sudo sysctl -w net.core.rmem_default=2097152

Discarding message because the queue is full

If you are getting a message like:

 [rviz]: Message Filter dropping message: frame 'laser' at time 1776876114.823 for reason 'discarding message because the queue is full'

This could be because there is no /tf topic available. This topic is used to describe the relationship between coordinate systems (robot position, lidar position, camera position etc).

If this is the case, you can changet the fixed frame reference to the lidar itself. Change the Global Options -> Fixed Frame option from map to laser to tell the system to use the laser as the base of all transforms.