I use them and the noise they make is why some still refer to bite alarms as buzzers. There are no single bleeps, peeps, pips or any of that warbling that goes on with the Delkims. I'm sure the buzzer from the Heron's sounder box would be well at home in the servant quarters of a mansion house.
A vane anemometer thus combines a propeller and a tail on the same axis to obtain accurate and precise wind speed and direction measurements from the same instrument. The speed of the fan is measured by a rev counter and converted to a windspeed by an electronic chip.
Wind has both speed and direction. Anemometers measure wind speed and wind vanes measure wind direction. A typical wind vane has a pointer in front and fins in back. When the wind is blowing, the wind vane points into the wind. For example, in a north wind, the wind vane points northward. A cup anemometer is a common tool to measure wind speed. The cups catch the wind and produce pressure difference inside and outside the cup. The pressure difference, along with the force of the wind, causes the cups to rotate.