Accelerometer.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Accelerometer: MonoBehaviour
{
    public bool isFlat = true;
    private RigidBody rigid;
    
    private void Start()
    {
        rigid = GetComponent<RigidBody>();
    }
    
    private void Update()
    {
        Vector3 tilt = Input.acceleration;
        
        if (isFlat)
            tilt = Quaternion.Euler(90, 0, 0) * tilt;
        
        rigid.AddForce(tilt);
    }
}