data export by windows PC client

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yche15Crazy
Beginner
Posts: 5
Joined: Thu Dec 06, 2018 12:22 pm

data export by windows PC client

Post by yche15Crazy » Thu Dec 06, 2018 12:25 pm

I have a little problem with the log-data by using windows PC client. I want collect the data of acceleration, gyro and stabilizer(p,r,y,t) simultaneously, means these data with the same timestamp. But they can't be added in one log block("save" is greyed out, progress bar over 100%. overload I guess), I can also not start the separate log blocks simultaneously. What should I do?

And, can I treat the data of stabilizer(pitch, roll. yaw, thrust) as input to the crazyflie?

Best regards

arnaud
Bitcraze
Posts: 1826
Joined: Tue Feb 06, 2007 12:36 pm

Re: data export by windows PC client

Post by arnaud » Thu Dec 06, 2018 12:53 pm

Hi,

You will need to create multiple log block in that case. The logs will not be synchronized unfortunatly, but every log packet are timestamped in the Crazyflie clock.

You can start and save more than one log block in the "Log Blocks" tab of the client.

I am not sure to understand the question about inputs, what are you trying to achieve?

yche15Crazy
Beginner
Posts: 5
Joined: Thu Dec 06, 2018 12:22 pm

Re: data export by windows PC client

Post by yche15Crazy » Thu Dec 06, 2018 5:02 pm

My target is to collect the data sets {stabilizer,gyro,acceleration} with synchronized timestamp.
There is my problem:
I can't add all these three logs in one block cause overloaded(progress bar shows 149%, so can't be saved).
If I add these three logs in three blocks respectively, they can't be synchronized started.

arnaud
Bitcraze
Posts: 1826
Joined: Tue Feb 06, 2007 12:36 pm

Re: data export by windows PC client

Post by arnaud » Fri Dec 07, 2018 9:27 am

Yes this is currently a limitation of the log subsystem. The reason is mainly that the log subsystem was designed more as a debug too rather than being a synchronous data collection system.

One way to solve this would be to modify the firmware to allows multiple log blocks to be sampled at the same time, I had started to look at that before and depending of how we want it to work it can be more or less complex.

Otherwise you need to implement a fully custom code in the firmware that sends custom packets with the data you need and implement the code to get them in python.

At what frequency do log the data?

yche15Crazy
Beginner
Posts: 5
Joined: Thu Dec 06, 2018 12:22 pm

Re: data export by windows PC client

Post by yche15Crazy » Sun Dec 09, 2018 10:01 pm

I set it with 100 ms.
Can I treat the log "stabilizer"as my input control data to the drone?
How can I get the specification of the logs?(What does each attribute mean and the unit of it)
And if I have to implement a fully custom code in the firmware, can you please give me some introduces and advices for it?

whoenig
Expert
Posts: 285
Joined: Mon Oct 27, 2014 2:55 am

Re: data export by windows PC client

Post by whoenig » Fri Dec 14, 2018 5:56 am

If you don't need the data in realtime, I suggest using the uSD deck, which already supports synchronous logging at a much higher data rate than what you can get over the radio, see https://wiki.bitcraze.io/projects:crazy ... ta_logging. It is even possible to get this data synchronous with the control loop (although I am not sure if that's in the official master branch, yet).

Unfortunately, there is no documentation on the log variables (and units) as of now. Currently, the only option is to look at (and to a certain degree understand) the firmware code. Of course, you can get help here in the forum if you have specific questions regarding log variables.

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