How to loop through a SimpleXMLElement object rest client in Php?

How to loop through a SimpleXMLElement object? This is what I have: I tried in many ways to iterate, but no success:

 Array
 (
    [status] => 1
    [data_nilai_siswa] => SimpleXMLElement Object
    (
        [item] => Array
            (
                [0] => SimpleXMLElement Object
                    (
                        [id_siswa] => 1
                        [nama_siswa] => 1
                        [n_bahasa] => 1.00
                        [n_matematika] => 1.00
                        [n_binggris] => 1.00
                    )

                [1] => SimpleXMLElement Object
                    (
                        [id_siswa] => 2
                        [nama_siswa] => 2
                        [n_bahasa] => 2.00
                        [n_matematika] => 2.00
                        [n_binggris] => 2.00
                    )
            )
       )
 )

i use library rest client philsturgeon/codeigniter-restclient and script rest client:

$xmlResponse = $this->rest->get('http://ift.tt/1oxbaFa');
$projects = array();

foreach($xmlResponse->project as $project) {
 $projects[$project->id_siswa] = $project->nama_siswa;
 echo 'Project ' . $project->nama_siswa . ' has ID ' . $project->id_siswa . PHP_EOL;
}

i get the error Message: Trying to get property of non-object? how to fix?