can't write strings to database

[eluser]illuzionist[/eluser]
ok now I did this and it just writes 0 to my locationGPS column, code is like this

Code:

$locationGPS = $this->uri->segment(3);
$data = array(
            'locationGPS' => $locationGPS
        );
$this->db->where('id', $id);
        $this->db->update('myTable', $data);

any thoughts on what might be wrong?