Page 1 of 1

data export by windows PC client

Posted: Thu Dec 06, 2018 12:25 pm
by yche15Crazy
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

Re: data export by windows PC client

Posted: Thu Dec 06, 2018 12:53 pm
by arnaud
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?

Re: data export by windows PC client

Posted: Thu Dec 06, 2018 5:02 pm
by yche15Crazy
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.

Re: data export by windows PC client

Posted: Fri Dec 07, 2018 9:27 am
by arnaud
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?

Re: data export by windows PC client

Posted: Sun Dec 09, 2018 10:01 pm
by yche15Crazy
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?

Re: data export by windows PC client

Posted: Fri Dec 14, 2018 5:56 am
by whoenig
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.