/stop_motor Service Does Not Stop the RP LIDAR Motor

[aaronwilhelm1]

Robot Model

Turtlebot4 Lite

ROS distro

Humble

Networking Configuration

Discovery Server

OS

Ubuntu 22.04

Built from source or installed?

Installed

Package version

1.0.5-1jammy.20240731.002306 for ros-humble-turtlebot4-node package

Type of issue

LIDAR

Expected behaviour

When running the command ros2 service call /stop_motor std_srvs/srv/Empty I expect the LIDAR to stop spinning.

Actual behaviour

When running the command ros2 service call /stop_motor std_srvs/srv/Empty the LIDAR does not stop spinning.

Error messages

ubuntu@ubuntu:~$ ros2 service call /stop_motor std_srvs/srv/Empty
waiting for service to become available...
requester: making request: std_srvs.srv.Empty_Request()

response:
std_srvs.srv.Empty_Response()

To Reproduce

1. Run ros2 service call /stop_motor std_srvs/srv/Empty

Other notes

I am doing this from an SSH session into the Raspberry Pi on the Turtlebot 4 Lite. I have tried it while the robot is both on the dock and off the dock. The robot is responsive in other ways, for instance I can still drive around the Turtlebot 4 using a controller. This also occurs with the /start_motor topic, i.e. when the LIDAR motor is not running and the /start_motor topic is called the motor does not start.

[RustyCPR]

Hi good afternoon @aaronwilhelm1
Can you please try this suggestion: #405 (comment)

Let me know,
Rusty

[aaronwilhelm1]

Manually installing it didn't help unfortunately, but on the page here it notes a bug:

There is currently a bug which results in the scan topic only stopping when the subscriber count drops from 1 or more to 0. This means that the motor will run until the scan topic is subscribed to and then unsubscribed from for the first time.

That's exactly what I'm running into. By just listening to the /scan topic from the command line and then stopping I'm able to get the lidar to stop spinning. Thanks for the help!