Crazyflie 2.0 IMU data

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sample
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Joined: Wed May 02, 2018 1:57 pm

Crazyflie 2.0 IMU data

Post by sample » Wed May 02, 2018 2:06 pm

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.



whoenig
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Re: Crazyflie 2.0 IMU data

Post by whoenig » 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.

sample
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Joined: Wed May 02, 2018 1:57 pm

Re: Crazyflie 2.0 IMU data

Post by sample » Thu May 03, 2018 6:30 am

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!

HC766
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Re: Crazyflie 2.0 IMU data

Post by HC766 » Tue Nov 26, 2019 2:49 pm

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?

whoenig
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Posts: 323
Joined: Mon Oct 27, 2014 2:55 am

Re: Crazyflie 2.0 IMU data

Post by whoenig » Thu Nov 28, 2019 1:30 am

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.

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