Rotating object based on USB Tilt Sensor

I'm trying to rotate an object based on an object with a tilt sensor connected via USB.

The accelerometer outputs a signed 16 bits for x,y,z, which I then convert to an angle.

         fAngleX = (float) (atan2(nAccelY, nAccelZ)+M_PI)*RAD_TO_DEG;
         fAngleY = (float) (atan2(nAccelZ, nAccelX)+M_PI)*RAD_TO_DEG;

I've searched and tried different ways of doing it*, but the object (.STEP) never rotates consistently, instead it quickly jumps all over the place as I rotate the device. As a test, I drew it in Processing and superman tracks the physical object fine.

http://imgur.com/0GDpMZ4

Maybe its better to use the raw value (not my computed angle) but not sure how else to do it.

 *
 float Angle = 30f;
 vector3 Axis = vector3.cross(MoveDirection.normalized, PlayerShip.transform.up);
 Playership.transform.Rotate(Axis, Angle);
 myTransform.rotation = Quaternion.Slerp(myTransform.rotation, targetRotation, slerpSpeedValue);

and

 *    
 dir.y = Input.acceleration.y;
 if (dir.y > .2)
     transform.Rotate(Vector3.up * (-rotSpeed * Time.deltaTime), Space.World);
 else if (dir.y < -.2)
     transform.Rotate(Vector3.up * (rotSpeed * Time.deltaTime), Space.World);

and

   *   
     accel = Vector3.Lerp(accel, Input.acceleration, filter * Time.deltaTime); // smooth filter 
     var dir = Vector3(-accel.y, accel.x, 0);  // map accel -Y and X to game X and Y directions     
     if (dir.sqrMagnitude > 1) dir.Normalize();  // limit dir vector to magnitude 1
       transform.Translate(dir * speed * Time.deltaTime); // move the object at the velocity defined in speed

      h = Input.GetAxis("Horizontal")*multiplier;
      v = Input.GetAxis("Vertical")*multiplier;
      transform.rotation = Quaternion.EulerAngles(new Vector3(h,0f,v));