Bitcraze Forums

Hi,

I would like to collect the position data from the crazy flie. Is there a way to capture and save the LPS position data to a file.

Regards
hyperglider

Hi,

I good way is to collect the data in a rosbag (see http://wiki.ros.org/rosbag/Commandline). If you need it in a text file, you can write a small script to convert the rosbag to whatever file format you like (see http://wiki.ros.org/rosbag/Code%20API).

Best,
Wolfgang

Hi,

I have tried rosbag to collect the position data and all it give me is below. I can not see / find where it is storing / using the log_ranges, crazyflie_position data.

Help please.


j@dualboot:~/bagfiles$ rosbag info 2016-08-23-20-58-34.bag
path: 2016-08-23-20-58-34.bag
version: 2.0
duration: 23.7s
start: Aug 23 2016 20:58:34.77 (1471949914.77)
end: Aug 23 2016 20:58:58.49 (1471949938.49)
size: 853.0 KB
messages: 6044
compression: none [1/1 chunks]
types: bitcraze_lps_estimator/RangeArray [6eea5c2b2055cd08369bcbebe9f0032b]
crazyflie_driver/GenericLogData [bfa79f36371fee74e53d96afde61049b]
diagnostic_msgs/DiagnosticArray [60810da900de1dd6ddd437c3503511da]
geometry_msgs/Point [4a842b65f413084dc2b10fb484ea7f17]
geometry_msgs/PoseStamped [d3812c3cbc69362b77dc0b19b345f8f5]
geometry_msgs/Twist [9f195f881246fdfa2798d1d3eebca84a]
rosgraph_msgs/Log [acffd30cd6b6de30f120938c17c593fb]
tf/tfMessage [94810edda583a504dfda3829e70d7eec]
tf2_msgs/TFMessage [94810edda583a504dfda3829e70d7eec]
visualization_msgs/Marker [18326976df9d29249efc939e00342cde]
visualization_msgs/MarkerArray [90da67007c26525f655c1c269094e39f]
topics: /anchors_markers 1 msg : visualization_msgs/MarkerArray
/crazyflie/cmd_vel 1176 msgs : geometry_msgs/Twist
/crazyflie/goal 706 msgs : geometry_msgs/PoseStamped
/crazyflie/log_ranges 787 msgs : crazyflie_driver/GenericLogData
/crazyflie_marker 771 msgs : visualization_msgs/Marker
/crazyflie_position 770 msgs : geometry_msgs/Point
/diagnostics 24 msgs : diagnostic_msgs/DiagnosticArray
/ranging 787 msgs : bitcraze_lps_estimator/RangeArray
/rosout 16 msgs : rosgraph_msgs/Log (5 connections)
/tf 1006 msgs : tf/tfMessage (2 connections)

Hi,

You can use the rosbag code API to print out the actual messages. One example is at the very bottom of this page: http://wiki.ros.org/rosbag/Code%20API. Just replace the filename (test.bag) with yours and the topic names with "crazyflie/log_ranges" to get the actual anchor distances.

Hope that helps,

Wolfgang

Wolfgang,

Thanks for that I now have access to data I am after.

regards
Hyperglider