MMA8652FC Rotation, referencial change

[sérgioneves]

Hello everyone,

Don't know if this is the correct location to ask this, to debate this topic.

I have the accelerometer (MMA8652FC) inside my equipment, such that when the equipment is placed in rest in a flat surface I have the G vector forces (0, 0, 1), like I show in the image (Forças_G_EN.png).
This would be the ideal position to place it inside a car, were would we know the position of the equipment / car.
I mean, we would know that the front of the car was at -X, back was at X, left was at -Y, right was at Y, floor was at -Z and roof was at Z. Image (EquipInCar_02_EN.png)

But the equipment is placed inside the car in a frontal position to the co-driver, and it can be in a rotated position.
It doesn't have a fixed position.

I show in image (EquipInCar_01_EN.png) an example of the positioning in a car.

My question is how to convert the values given by the accelerometer from the position in the car (EquipInCar_01_EN.png) to the ideal position (EquipInCar_02_EN.png)?
Anyone can help on this?

Regards,

Sergio