Using Accelerometer to Build 2D Racing Game

I want to develop racing game in 2D using Accelerometer with Unity. The sensor will make car rotate left or right like this figure.

When i flip smartphone to right, car will turn right, and when i flip to left, car will turn left. I use accelerometer sensor to turn the car when flip smartphone.

My Code :

     public class accel : MonoBehaviour 
     {
         public MoveController mc;
         void Update () 
             {
                 transform.Translate(0,-Input.acceleration.x, 0);
                 if (Input.acceleration.x > 0) {
                     mc.degree -= 10;
                     mc.derajat-=10;
                 }
                 else if (Input.acceleration.x < -0) {
                     mc.degree += 10;
                     mc.derajat+=10;
                 }
                 else {
                     mc.degree += 0;
                     mc.derajat+= 0;
                 }
             }
 }

Class MoveController :

 using UnityEngine;
 using System.Collections;
 
 public class MoveController : MonoBehaviour {
 
     public bool stop = false;
     public enum ButtonList {left,right,forward,stop};
     public float currspeed = 1.0f;
     public float acceleration = 5f;
     public float maxspeed = 12f;
     public float degree = 10f;
     public float derajat = 10f;
     public bool jalan;
     public Camera camera;
     public SpriteRenderer redcar;
     public float sudut;
 
     public void setActiveStop() {
         stop = true;
     }
 
     public void setUnactiveStop() {
         stop = false;
     }
 
     public bool getStop() {
         return stop;
     }
 
     public bool getNotStop() {
         return !stop;
     }
 
     void Start () {
         this.setUnactiveStop ();    
         jalan = false;
 
     }
 
     // Update is called once per frame
     void Update () {
         this.start_game (); 
 
     }
 
     public void start_game() {
         if (getNotStop()) {
             redcar.transform.rotation=Quaternion.Euler(0,0,degree);
             camera.transform.rotation=Quaternion.Euler(0,0,derajat);
 
             sudut=redcar.transform.rotation.z;
             redcar.transform.Translate((currspeed*Mathf.Cos(sudut*Mathf.PI/180))*1*Time.deltaTime,
                                        (currspeed*Mathf.Sin(sudut*Mathf.PI/180))*1*Time.deltaTime,
                                        0);
             camera.transform.Translate((currspeed*Mathf.Cos(sudut*Mathf.PI/180))*1*Time.deltaTime,
                                        (currspeed*Mathf.Sin(sudut*Mathf.PI/180))*1*Time.deltaTime,
                                        0);
 
         }
         jalan = true;
 
     }
 }

When i build and run in my smartphone, the car doesn't stop to rotate and its rotation is too fast. I want to modify Update function in first code, in order to the car can rotate / turn right-left smoothly.

So, how to fix it?