I'm trying logging data with micro sd-card deck. Currently I came across these questions (all related to logging on sd card of course)

1/ Is it possible to log custom variables without modifying the firmware ? If so, how to proceed. I looked at the scripts https://github.com/bitcraze/crazyflie-f ... nctions.py and https://github.com/bitcraze/crazyflie-f ... example.py. Are these modifiable for this purpose ?

2/ Should the firmware need to be editted, where should I start ?

3/ I need to log the position (x,y,z coordinates), orientation (roll/pitch/yaw), velocity/acceleration (linear as well as angular). Are these already available in LogTOC (under which names in this case) ?

4/ What data do the barometer, accelerator and magnetometer return ? All are in x,y,z coordinates but how can I make sense of them ?

I understand those are not few questions and would appreciate every little help there is .

## Logging custom variables using sdcard

### Re: Logging custom variables using sdcard

There is some ongoing work with the micro sd card logging by a community member. I'm not sure about the status yet though but I think the idea is to do what you request. Because of this:

1. Unfortunately not yet.

2. Easiest would be to hack the usddeck.c file and add variables you would like to log.

3 and 4. Basically add the variables the same way as the acc, gyro is added. Variables you need:

Position in meters:

kalman.stateX

kalman.stateY

kalman.stateZ

Attitude in degrees:

stabilizer.roll

stabilizer.pitch

stabilizer.yaw

Angular velocity in deg/s:

gyro.x

gyro.y

gyro.z

Accelerometer in m/s2:

acc.x

acc.y

acc.z

One problem though is that logging to micro-SD together with LPS, the SPI buss gets overloaded. Se this bug, and it is not solved yet

1. Unfortunately not yet.

2. Easiest would be to hack the usddeck.c file and add variables you would like to log.

3 and 4. Basically add the variables the same way as the acc, gyro is added. Variables you need:

Position in meters:

kalman.stateX

kalman.stateY

kalman.stateZ

Attitude in degrees:

stabilizer.roll

stabilizer.pitch

stabilizer.yaw

Angular velocity in deg/s:

gyro.x

gyro.y

gyro.z

Accelerometer in m/s2:

acc.x

acc.y

acc.z

One problem though is that logging to micro-SD together with LPS, the SPI buss gets overloaded. Se this bug, and it is not solved yet

### Re: Logging custom variables using sdcard

So there is not yet the variables to measure linear velocity, but it can be approximated by integrating the linear acceleration right ?

### Re: Logging custom variables using sdcard

The kalman filter has variable that tracks the linear velocity as well: https://github.com/bitcraze/crazyflie-f ... #L229-L232, all the states are available as log: https://github.com/bitcraze/crazyflie-f ... 1452-L1460