An airflow detecting system includes a tubular structure having an inner surface defining an interior of the tubular structure, one open end and an opposite open end. The tubular structure is configured to receive and expel air through both the one end and the opposite end. The system further includes a flap connected to the inner surface of the tubular structure by a hinge. The flap is configured to impede airflow within the interior of the tubular structure upon the application of differential pressure across the two ends of the tubular structure. The system further includes a device attached to the flap in a position in which the device spans the hinge. The device is configured to measure a parameter associated with the movement of the flap in response to airflow within the interior of the tubular structure. Other embodiments and methods are further disclosed.