mb_str_split.php

<?php

function mb_str_split($string,$string_length=1) {
        if(mb_strlen($string) > $string_length || !$string_length) {
                do {    
                        $c = mb_strlen($string);
                        $parts[] = mb_substr($string,0,$string_length);
                        $string = mb_substr($string,$string_length);
                }while(!empty($string));
        } else {         
                $parts = array($string);
        }
        return $parts;
}