Check if a user is online codeigniter without using sessions using time() instead

Question

When my user logs in it updates the last_active and last_visit width time().

Once user has logged on any page that is visits it updates the users last_active and last_visit column.

I am trying to figure out the best way so on the users profile page it can show if user is online or not even if in different browser.

http://sample.com/user/1

I can not seem to get it correct. It still shows user as online in other browsers when infact the user has logged out

Question how can I check if the user is online or not even if in a different browser?

I have looked at How to see if a user is online in a website with php and mysql driven databases?

And PHP Check if a user is online

The links not help.

if(date("H:i:s", $udata['last_active']) == date("H:i:s", $udata['last_visit']) && date("H:i:s", $udata['last_active']) != date("H:i:s", strtotime("+1 min"))) {
    $this->data['active'] = 1;
} else {
    $this->data['active'] = 0;
}

Model

<?php 

class User_model extends CI_Model {

public function __construct() {
    parent::__construct();

        if ($this->islogged() == 1) {

            $this->db->where('user_id', $this->getuserid());
            $query = $this->db->get($this->db->dbprefix  . 'user_data');

            if ($query->num_rows() == 1) {

                $user_data = array(
                    'last_active' => time(),
                    'last_visit' => time(),
                    'ip_address' => $this->input->ip_address()
                );

                $this->db->where('user_id', $query->row()->user_id);
                $this->db->update($this->db->dbprefix . 'user_data', $user_data);
            }

        } else {

            $this->logout();
        }
    }

}

Controller

<?php

class User extends MY_Controller {

    public $data;

    public function __construct() {
        parent::__construct();
        $this->load->library('elapsed_time');
        $this->load->model('forum/thread_model');
        $this->load->model('user/user_model');
    }

    public function index($user_id) {
        $udata = $this->user_model->getuser($user_id);

        if ($udata) {

            // Titles
            $this->data['title'] = 'Profile of ' . $udata['username'];
            $this->data['heading_title'] = 'Forum Info';

            // Page Data
            $this->data['profile_username'] = $udata['username'];

            if(date("H:i:s", $udata['last_active']) == date("H:i:s", $udata['last_visit']) && date("H:i:s", $udata['last_active']) != date("H:i:s", strtotime("+1 min"))) {
                $this->data['active'] = 1;
            } else {
                $this->data['active'] = 0;
            }

            $this->data['how_long_was_online'] = 'Created account but not logged in yet!';
            $this->data['date_created'] = date('d-m-Y h:i:s' , $udata['date_created']);

            $this->data['avatar'] = ($udata['avatar']) ? $udata['avatar'] : 'holder.js/100px180';

            $this->data['total_questions'] = $this->thread_model->total_users_thread_questions($user_id);
            $this->data['total_threads'] = $this->thread_model->total_users_threads($user_id);

            // Page Links
            $this->data['users_questions'] = site_url('search/questions/' . $user_id);
            $this->data['users_threads'] = site_url('search/threads/' . $user_id);
            $this->data['pm'] = site_url('mail/pm/' . $user_id);
            $this->data['email'] = site_url('mail/email/' . $user_id);

            $this->data['children'] = array(
                'common/header',
                'common/footer',
                'common/navbar' 
            );

            $this->load->render('user/user', $this->data);

        } else {

            redirect('not_found');
        }
    }
}