Logging data to pixhawk SD card

1

Hello guys…

After a long time I have started working with pixhawk again. I need a bit of help with data logging to px4 sd card.

I am working the 5 hole probe and using Teensy & Probe I can get velocity , alpha and beta of the vehicle. I’m able to read this values in pixhawk telem1 port. I want this parameters also to be logged as soon as the controller is armed. Can someone point me in a direction how to do this ?

Thanks in advance

2

How are you reading them within PX4? If you publish the messages with uORB they can be directly logged.
https://dev.px4.io/en/middleware/uorb.html
https://dev.px4.io/en/log/logging.html

3

Thanks man…just some doubts…

  1. How the topic is getting linked to the uORB publishing/subscribing system ? Do I need to add the topic to any topic list or something ?

  2. I’m sending the data serially to telem 1 in pixhawk and i can read the data from that port ( have written a code for that in the example section ). For publishing to the topic I can use the same code in modules with ‘#include <uORB/topics/topic_name.h>’ header right ?

  3. And for logging : " The list of logged topics can be customized with a file on the SD card. Create a file etc/logging/logger_topics.txt " , there is no etc folder on the SD card itself ! There is just the log folder . Does adding here will append the topics to the log file created when pixhwak is armed.

4

Thanks Dagar…I’m able to log the data to the SD card now ( by creating a file etc/logging/logger_topics.txt on the sd card ).

I would like to add my topic to the default log file generated by pixhawk. Will it work if I just add my topic to the logger.cpp ?

Thanks

1 Like
5

Yes, just keep in mind you have to keep the number of logged topics under the maximum number of file descriptors on nuttx. I think it’s currently 53 or 54.

6

Its not working for me. I cant identify my mistake here.

I have added the topic to logger.cpp ( in add_common_topics ) and generated the log file using logger on but when I convert it into csv file ( using ulog2csv) I cant find a file with my topic name in it.

But if I add etc/logging/logger_topics.txt and add my topic to the text file , then I can see logging taking place. But when I try generating csv file using ulog2csv it is not generating the csv file. Cant find the mistake !!

7

Do you see any messages in the console or if you upload the log to http://logs.px4.io/? Did you check the file descriptor limit? You’ll probably need to remove something from the default list in logger.cpp.

8

hello dagar

Just need a little bit of information.I’m able to log the values now ( either by adding the topic name in logger_topics.txt or adding the topic name in logger.cpp ) . But the issue is until and unless I start mu publisher code ( written as a daemon app ) explicitly , my topics wont get logged. I have to start my publisher code first ( probe_pub start ) and then start logger on in both cases so that I can get my topic values to get logged.

I want my daemon app to run once the controller is powered on ? How can I do that ?

Thanks in advance