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Crazyflie 2.0 IMU data

Posted: Wed May 02, 2018 2:06 pm
by sample
Hi everyone,

I want to extract raw IMU data from CF2.0. For the last few days I've been using rostopic echo /crazyflie/imu to read the data. My question is: when I read data using this method do I get raw data from the IMU or the data I get has been filtered in some way? If the data has been filtered, how do I get unfiltered data?

Thanks in advance.

Re: Crazyflie 2.0 IMU data

Posted: Wed May 02, 2018 4:39 pm
by whoenig
This is unfiltered, but converted to the standard ROS units. However, the sampling frequency over the radio is very limited (100 Hz max), while the IMU generates data up to 4 kHz. If you really want the raw data at full frequency, you'll need a wired connection (I used a SEGGER J-LINK debugger before to stream data at full speed). Other people also experimented with logging to a uSD card.

Re: Crazyflie 2.0 IMU data

Posted: Thu May 03, 2018 6:30 am
by sample
whoenig wrote: Wed May 02, 2018 4:39 pm This is unfiltered, but converted to the standard ROS units. However, the sampling frequency over the radio is very limited (100 Hz max), while the IMU generates data up to 4 kHz. If you really want the raw data at full frequency, you'll need a wired connection (I used a SEGGER J-LINK debugger before to stream data at full speed). Other people also experimented with logging to a uSD card.
Thank you for quick answer, cheers!

Re: Crazyflie 2.0 IMU data

Posted: Tue Nov 26, 2019 2:49 pm
by HC766
Hi, whoenig. I saw that you said the imu in ROS is already converted to ROS units. Can I ask what's the different between ROS units and the raw imu data unit?

Re: Crazyflie 2.0 IMU data

Posted: Thu Nov 28, 2019 1:30 am
by whoenig
It depends on what variables you log. In this case it's just non-SI units to SI units, see https://github.com/whoenig/crazyflie_ro ... #L596-L604.