Unity: Changing the alpha color of an object in random times(C#)

Hello there,
I'm trying to write a script to turn the lights off in my game at random times.
the lights are just a 2d images with 0.4 alpha color.
I wanted to change the alpha color in the sprite renderer to 0 every few seconds(random between 0-10) for 3 seconds and back to 0.4 again and start over.

this is my code so far for the lights:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Lightning : MonoBehaviour {
6.     private Color temp;
7.  
8.     void Start () {
9.         temp = this.gameObject.GetComponent<SpriteRenderer>().color;
10.         StartCoroutine(Waiter());
11.  
12.     }
13.  
14.     IEnumerator Waiter()
15.     {
16.         int wait_time = Random.Range(0, 10);
17.         yield return new WaitForSecondsRealtime(wait_time);
18.         temp.a = 0f;
19.         yield return new WaitForSeconds(3);
20.         temp.a = 0.4f;
21.         StartCoroutine(Waiter());
22.     }
23. }

for some reason nothing happens in the scene and there is no errors in the console ether...
can anyone please tell me what I'm doing wrong here?

 

The sprite colour isn't a reference type, so you need to change a colour and then assign it. Try this;

Code (CSharp):

1. using System.Collections;
2. using UnityEngine;
3.  
4. public class Lightning : MonoBehaviour
5. {
6.     private SpriteRenderer _sRenderer;
7.     private WaitForSeconds _threeSecs = new WaitForSeconds(3f);
8.  
9.     private Color _spriteColour;
10.     private float _originalalpha;
11.  
12.     private void Start()
13.     {
14.         _sRenderer = GetComponent<SpriteRenderer>();
15.         StartCoroutine(Waiter());
16.  
17.         _spriteColour = _sRenderer.color;
18.         _originalalpha = _spriteColour.a;
19.     }
20.  
21.     IEnumerator Waiter()
22.     {
23.         while (true)
24.         {
25.             int wait_time = Random.Range(1, 11);
26.  
27.             yield return new WaitForSecondsRealtime(wait_time);
28.  
29.             _spriteColour.a = 0f;
30.             _sRenderer.color = _spriteColour;
31.  
32.             yield return _threeSecs;
33.  
34.             _spriteColour.a = _originalalpha;
35.             _sRenderer.color = _spriteColour;
36.         }      
37.     }
38. }

 

Thank you so much!