FireBullet

FireBullet.cs

using UnityEngine;
using System.Collections;

public class FireBullet : MonoBehaviour {

	public GameObject bullet;
	public float maxCoolDown;

	private float timer;
	private bool canShoot;

	// Use this for initialization
	void Start () {
		timer = maxCoolDown;
		canShoot = true;
	}
	
	// Update is called once per frame
	void Update () {

		timer = timer - Time.deltaTime;

		if(timer <= 0){
			canShoot = true;
		}

		if(Input.GetKey(KeyCode.Space) && canShoot){
			Instantiate(bullet,
			            this.transform.position, 
			            Quaternion.identity);
			canShoot = false;
			timer = maxCoolDown;
		}

	}
}