This gist is to use WordPress inbuilt function wp_is_mobile excluding the ipad view port

custom_wp_is_mobile.php

function custom_wp_is_mobile() {
    static $is_mobile;

    if ( isset($is_mobile) )
        return $is_mobile;

    if ( empty($_SERVER['HTTP_USER_AGENT']) ) {
        $is_mobile = false;
    } elseif (
        strpos($_SERVER['HTTP_USER_AGENT'], 'Android') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Silk/') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Kindle') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'BlackBerry') !== false
        || strpos($_SERVER['HTTP_USER_AGENT'], 'Opera Mini') !== false ) {
            $is_mobile = true;
    } elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'Mobile') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'iPad') == false) {
            $is_mobile = true;
    } elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'iPad') !== false) {
        $is_mobile = false;
    } else {
        $is_mobile = false;
    }

    return $is_mobile;
}