Adding actions immediatly after login

[Patrick]

Hi,

I have a function I want to run immediately after a user has loged in/been successfully authenticated.

For background - I'm storing wether a user has logged in using an iPad and am using and separate mobile detect script.

Anyway, here's my code - hope you can help

/*

Plugin Name: STW - Mobile Detect

Description: Provide Mobile detect functionality based on http://code.google.com/p/php-mobile-detect/

Version: 0.1

*/

require_once('mobile_detect.php');

$mobile = new Mobile_Detect();

function log_my_device() {

global $current_user, $mobile;

$username = $current_user->user_login;

$userid = $current_user->ID;

$loggedIn = is_user_logged_in();

if ($loggedIn){

if ( $mobile->isiPad() ){

update_user_meta( $userid, 'IPad_user', '1');

}

}

}

add_action('wp_signon', 'log_my_device');