CodeIgniter : Setting up jQuery and post data to Controller using jQuery

I added

<script type="text/javasript" src="<?=base_url()?>js/jquery-1.7.2.min.js"></script>

in application/views/templatess/header.php and to post data to Controller using jQuery I wrote

<script>

$(document).ready(function(){

    $('#submit').click(function() {
        $.ajax({
            type : 'POST',
            url : '/projects/create',
            data: {
                pro_name : $('#pro_name').val()
            },
            success:function (data) {
                $("#log_msg").html(data);
            }          
        });
    });

});
</script>

in my view file: application/views/project/create.php and the controller exists in application/controllers/projects.php

In my view named create.php the complete code is:

<label for="pro_name">Project Name</label>
<input type="input" id="pro_name" name="pro_name" />
<br />
<input type="submit" id="submit" name="submit" value="Create" />

<script>

$(document).ready(function(){

    $('#submit').click(function() {
        $.ajax({
            type : 'POST',
            url : '/projects/create',
            data: {
                email : $('#pro_name').val()
            },
            success:function (data) {
                $("#log_msg").html(data);
            }          
        });
    });

});
</script> 

and my controller named projects contains

class Projects extends CI_Controller {
    public function __construct()
    {
        parent::__construct();
        $this->load->model('projects_model');
        $this->load->helper('url');
        $this->load->helper('html');

        $this->load->helper('form');
        $this->load->library('form_validation');
    }

    public function create()
    {
        echo $this->input->post('pro_name');

        $data['title'] = 'SPARCS | Create Project';

        $this->form_validation->set_rules('pro_name', 'Name', 'required');
        $this->form_validation->set_rules('pro_client', 'Client', 'required');
        $this->form_validation->set_rules('pro_loc_city', 'City', 'required');
        $this->form_validation->set_rules('pro_loc_state', 'State', 'required');
        $this->form_validation->set_rules('pro_size', 'Project Size', 'required');      
        $this->form_validation->set_rules('pro_desc', 'Description', 'required');

        if ($this->form_validation->run() === FALSE)
        {
            $this->load->view('templates/header', $data);   
            $this->load->view('projects/create');
            $this->load->view('templates/footer');

        }
        else
        {
            // If project name already exists?

            $query = $this->projects_model->if_exists($this->input->post('pro_name'));

            if ( sizeof($query) == 0) {

                //$this->projects_model->set_project();             
                $data['message'] = 'Add successfully';

            } else {

                $data['message'] = 'Project name already exists';
            }

            $this->load->view('projects/log_message', $data);
        }
    }
}

But browser says $ is not defined

Now please let me know how to setup jQuery in CodeIgniter and what is the correct way to pass data to the controller and also show response send back from the controller