...

      $self->{timer} = Wx::Timer->new();
      $self->{timer}->Start(1000);

	$self->__set_properties();
	$self->__do_layout();

	Wx::Event::EVT_TIMER($self->{timer}, -1 , \&gewicht);

...

sub gewicht {
	my ($self, $event) = @_;

      my @wert = wiegen(1);
      $self->{kg}->SetLabel("ja")

}

...