Gyroscope.gravity

public Vector3 gravity ;

説明

デバイスの参照フレームでの正確な重力加速度のベクトルを返します

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public float movementScale;
    void Update() {
        Vector3 pos = transform.position;
        pos.y = Vector3.Dot(Input.gyro.gravity, Vector3.up) * movementScale;
        transform.position = pos;
    }
}