Orienting A Custom VR Remote Properly

So, Im sending values from an MPU-9250 sensor on an arduino into unity which is acting as a makeshift vr controller, and although it rotates... it doesnt do so properly. For example, if I rotate it up, itll rotate sideways, etc etc. I know that its an issue with how to set the parent gameobjects orientation, but Im not sure how to figure that out. Is it just trial an error? That would be tedious. Either way, responses are greatly appreciated, Thank you! =)