while (1)
{
    foreach my $connection (my @can_read = $select->can_read(5))
    {
        if ($connection == $listen_socket)
        {
                my $client = $listen_socket->accept();
                $select->add($client);

                $client->recv($data,1024);
                if ($data) {
                        my @received = unpack('C*', $data);
                        my $id=join('', map {sprintf('%02x', $_)} @received);

                        if (exists($con_hash{ $id })) {
                                        if ($con_hash{ $id } != $client) {
                                                &do_log("ID $id changed socket from $con_hash{ $id } to $client, updating entry");
                                                $con_hash{ $id }=$client;
                                        }
                                        else {
                                                &do_log("ID $id re-connected on same socket $client");
                                        }
                        }
                        else {
                                if ($id) {
                                        &do_log("Creating connection entry for ID $id");
                                        $con_hash{ $id }=$client;
                                        while( my ($k, $v) = each %con_hash ) {
                                                &do_log ("Connected ID: $k, socket: $v");
                                        }
                                }
                                else {
                                        &do_log("ERROR: Something is wrong");
                                }
                        }

                }
                else {

                        &do_log("ERROR: Something else is wrong");
                }
        }
        else
        {

               &do_log("Closing connection to $connection");
                while( my ($key, $value) = each %con_hash ) {
                        if ($value == $connection) {
                                &do_log("Deleting connection entry for ID $key");
                                delete $con_hash{$key};
                        }
                }
                while( my ($k, $v) = each %con_hash ) {
                        &do_log ("Connected ID: $k, socket: $v");
                    }


                $select->remove($connection);
                close($connection);


        }
    }

    foreach my $connection (my @can_write = $select->can_write(5))
    {
                my @send_dec=qw(T E S T);
                my $send_hex=pack('C*', @send_dec);

                while( my ($con_id, $sock) = each %con_hash ) {
                                &do_log("Sending data to ID $con_id via socket $sock: ".join('', map {sprintf('%02x', $_)} @send_dec));
                                $sock->send($send_hex);
                                $sock->recv($data,1024);
                                my @recv_dec = unpack('C*', $data);
                                &do_log("Received data from ID $con_id via socket $sock: ".join('', map {sprintf('%02x', $_)} @recv_dec));
                }
   }
   sleep (5);
}