how can I detect the orientation with respect to the initial position as z pointing downwards and the other two axis according to the right-hand coordinate system?

[RKuma.12]

Actually i am working for telematics company and I am design a device to detecting the harsh breaking , harsh acceleration and harsh cornering event in a vehicle. so pls let me know if any suggestion is their.

[Eleon BORLINI]

hi, which device are you using (and which sensor grade do you need)? Taking as example a 6-axis sensor (axl+gyro), to obtain the position starting from a point in space you should double integrate the acceleration dataout (axl) and integrate the angular speed dataout (gyro) on the 3 axis (this is the concept of dead reckoning). It is not so easy to get accurate value, you have to properly filter the raw data...

On the other hand, if you want to detect "harsh breaking , harsh acceleration and harsh cornering event", it could be  enough to define threshold on the acceleration and the rotation and use a sensor that allows you to generate an interrupt in case of such harsh event (if the FS required is not too high, there are sensors such as LSM6DSOX that enable you to create a decision tree to automatically classify the intensity of the acceleration or of the rotation you are measuring, defining properly your labels)

Regards

[RKuma.12]

sir i am using in a vehicle tracing device and i am using LSM6DS3 sensor.

[RKuma.12]

Sir, I am able to calibrate the data of gyro and accelerometer at the static case but when it comes to dynamic case it fails. can you suggest me how to do it in case of dyanmic motion, As gyro data give only relative rotation not absolute rotation.

[Eleon BORLINI]

​hi, for an absolute reference you could use a magnetometer such as the LIS2MDL, which gives you the absolute position with respect to the earth. regards

[AvaTar]

> hi, for an absolute reference you could use a magnetometer such as the LIS2MDL, which gives you the absolute position with respect to the earth. regards

In a metallic vehicle, with plenty of EM field generating systems, I see a potential problem here.

> Actually i am working for telematics company and I am design a device to detecting the harsh breaking , harsh acceleration and harsh cornering event in a vehicle. so pls let me know if any suggestion is their.

How about the mathematical model (equations) of a moving body, a.k.a. Newton's laws ?

Applying physical properties of the vehicle and range and resolution of the sensors yields a starting point for your design.

[Eleon BORLINI]

​hi AvaTar, I agree, but one could place the pcb in a proper area and if the materials are not hard ferromagnetic as in a lot of cases it could be used in a car environment (some customer use it https://community.st.com/s/question/0D50X0000AAHw3HSQT/lis3mdl-for-detecting-car-occupancy-in-parking-space)