Accelerometer and drag

I'm trying to spin an object that must retain the force applyed by the accelerometer for quite some time. For some reasone the code is not working even if the same come works very well with swipes.

 using UnityEngine;
 using System.Collections;
 
 public class GyroControls : MonoBehaviour 
 {
 
     public GameObject m_objectToMove;
     public GameObject m_sphereBackground;
     public float drag = 1f;
     
     private float _rotValue = 0;
     
     
     public static GyroControls Instance{set;get;}
     
     void Awake () 
     {
         // First we check if there are any other instances conflicting
         if(Instance != null && Instance != this)
         {
             // If that is the case, we destroy other instances
             Destroy(gameObject);
         }
 
         // Here we save our singleton instance
         Instance = this;
 
         // Furthermore we make sure that we don't destroy between scenes (this is optional)
         DontDestroyOnLoad(gameObject);
     }
 
     
     
     void FixedUpdate() 
     {
         ProcessInput(Input.acceleration);
         ProcessMotion(Time.deltaTime);
         ProcessPhysics(Time.deltaTime);
     }
     
     
     
     void ProcessInput(Vector3 dir)
     {    
         _rotValue += dir.x;
     }
 
     
     
     void ProcessMotion(float deltaTime)
     {
         float _turnValue = _rotValue  * deltaTime;
         
         m_objectToMove.transform.Rotate(new Vector3(0,0,_turnValue));
         m_sphereBackground.transform.Rotate( new Vector3(0,0,_turnValue));    
     }
     
     void ProcessPhysics(float deltaTime)
     {
         
         // drag must be improved as function of _rotValue
         
         if(_rotValue < -clamp)
                 _rotValue += drag;
         else if(_rotValue > clamp)
                 _rotValue -= drag;
     }
 }