Send email after record add

I have a field called "id_nome_progetto" in the table "_jb_progetti"

Each time a new record is added I want to send an email to "xxxx@xxxxx.com" with the content of the "id_nome_progetto" field in the message body.
I tried with this:
$email="xxxx@xxxxx.com";

$message="";

$subject="Sample subject";

$message.="id_nome_progetto:".$values["id_nome_progetto"]."\r\n";

mail($email, $subject, $message);
what's wrong?