Comment by 1024son for The linux account you are using to run ROS probably does not have read-write permission for the device /dev/i2c-0. As a quick hack, you can issue this command:sudo chmod 666 /dev/i2c-0but this will need to be repeated if you reboot the machine.The better thing to do is to create a udev rule which will change the permissions on this device each time the machine boots.

Thanks for replying. after running `sudo chmod 666 /dev/i2c-0`, the error message changes `what(): i2c device open failed` to `what(): incorrect chip ID`. The full error: `PARAMETERS * /imu/imu_node/address: 40 * /imu/imu_node/device: /dev/i2c-0 * /imu/imu_node/frame_id: imu * /rosdistro: noetic * /rosversion: 1.15.14` `NODES /imu/ imu_node (imu_bno055/bno055_i2c_node)` `ROS_MASTER_URI=http://localhost:11311` `process[imu/imu_node-1]: started with pid [4568] terminate called after throwing an instance of 'std::runtime_error' what(): incorrect chip ID` `[imu/imu_node-1] process has died [pid 4568, exit code -6, cmd /home/odroid/catkin_ws/devel/lib/imu_bno055/bno055_i2c_node __name:=imu_node __log:=/home/odroid/.ros/log/dec645e4-9e44-11ec-bc5c-001e06489d9b/imu-imu_node-1.log].` `log file: /home/odroid/.ros/log/dec645e4-9e44-11ec-bc5c-001e06489d9b/imu-imu_node-1*.log ^C[imu/imu_node-1] killing on exit shutting down processing monitor...`