Hi friends here is the php code to know whenever google crawl your website.
it automatically sends you an email on your email id.

< ?php
if ( strpos( $_SERVER['HTTP_USER_AGENT'], ‘Googlebot’ ) !== false )
{
// Your email address
$email_address = ‘you@yourdomain.com’;
// Send yourself an email
mail($email_address,’Googlebot Alert’, ‘The Googlebot has visited your page: ‘.$_SERVER['REQUEST_URI']);
}
?>

If you have any query feel free to contact me