Collecting objects for limited time after colliding magnet, how can i do that?,

Hello guys, I have a script in my game that I want to run when the character collides the magnet in the level. Currently, the character is pulling all objects without colliding the magnet. I also want character to attract objects for 5-10 seconds after colliding the magnet. How can i do that?

https://youtu.be/MnxcAajbCCs this is the game i am working on.

This is the script code below so this script should work only when i collide with magnet. Magnet must work for 5-10 second then this script shouldn't work again.

 using System.Collections.Generic;
 using UnityEngine;
 
 public class CoinsController : MonoBehaviour
 {
     [SerializeField]
     private int numberOfCoins;
 
     [SerializeField]
     private float radius;
 
     [SerializeField]
     private string coinTag;
 
     [SerializeField]
     private float pickupSpeed;
 
     [SerializeField]
     private float pickupDistance;
 
     private List<Transform> coins;
 
     void Start()
     {
         coins = new List<Transform>();
     }
 
     void FixedUpdate()
     {
         Collider[] hitColliders = Physics.OverlapSphere(transform.position, radius);
 
         for (int i = 0; i < hitColliders.Length; i++)
         {
             if (hitColliders[i].CompareTag(coinTag) &&
                 !coins.Contains(hitColliders[i].transform))
             {
                 coins.Add(hitColliders[i].transform);
             }
         }
 
         for (int i = 0; i < coins.Count; i++)
         {
             if (Vector3.Distance(transform.position, coins[i].position) <= pickupDistance)
             {
                 numberOfCoins += 1;
                 coins[i].gameObject.SetActive(false);
                 coins.Remove(coins[i]);
             }
             else
             {
                 float step = pickupSpeed * Time.deltaTime;
                 coins[i].position = Vector3.MoveTowards(coins[i].position, transform.position, step);
             }
         }
     }
 }