如何在PHP中将ASCII转换为ISO-8859-1？

Question

I'm currently trying to figure out how to convert an ASCII encoded string to ISO-8859-1 encoding to be used for utf8_encode() to display special characters like "ñ" but I can't seem to make it work. In need of help.

I've already tried this iconv(mb_detect_encoding($text, mb_detect_order(), true), "ISO-8859-1", $text); and this mb_convert_encoding($text, "ISO-8859-1"); and also this mb_convert_encoding($text, "ASCII", "ISO-8859-1"); but it doesn't work, the string is still ASCII encoded.

I've created a temporary solution for this by creating a lookup table using the string provided by reading each character of the string. But I want to use the php built-in functions, is this possible?

Here is my code:

<?php

function convertString($text) {

    $text = iconv(mb_detect_encoding($text, mb_detect_order(), true), "ISO-8859-1", $text);
    echo mb_detect_encoding($text) .'<br/>'; // to check what encoding the string is in, displays ASCII
    return utf8_encode($text);

}

echo convertString('\xc3\xb1');

?>