def stop(self):
        """Stop hardware and close connections."""
        if self._light_system:
            self._light_system.stop()

        for task in self._poll_task.values():
            task.cancel()

        self._poll_task = {}

        if self._incand_task:
            self._incand_task.cancel()
            self._incand_task = None

        for connections in self.serial_connections:
            connections.stop()

        self.serial_connections = []