How to Make Your Own Anemometer

Wind is common phenomena in every environment in the world. Wind often carries or distributes pollutants, cool and warm air, influencing the climate of a region. Wind is often used to monitor weather patterns, including wind direction and speed. Knowing the speed and direction of winds allows engineers to know the exact place where a building or house may be constructed. This prevents a construction from receiving prevailing winds that could affect it climatologically.

The anemometer is a device used to measure the speed of wind and is most often used in meteorology and aerodynamics. The first anemometer was invented in the 15th century, and many others have been developed since then. Throughout this hub, I’m going to show you how to build a three cup anemometer.

Things Needed to Make a Three Cup Anemometer

  • Two feet of 20 gauge wire
  • Three polystyrene cups
  • Mini electric motor
  • Pair of scissors
  • Tripod
  • Black masking tape
  • Plastiline
  • Blue marker

To make this anemometer, I used things that I had around the house. As the vertical shaft for this anemometer, I’m using a photographic tripod. A mini electrical motor is going to serve as the rotor for the shaft. On the electrical motor’s tiny pulley, I will place the horizontal wire arms and at the end of the wire arms, the cups.

Things Needed
Things Needed | Source

How to Make a Three Cup Anemometer?

To begin this project, place the electrical motor over the end of the tripod. The motor has a flat base that can sit on the tripod. You may use glue or plastiline to attach the motor to the tripod. I used plastiline, but if you decide to make this permanent, you may choose to solder the motor to the tripod.

Tripod and Motor
Tripod and Motor | Source

With the wire, make a set of three horizontal arms. these horizontal arms will hold the cups at equal angles to each other on a vertical shaft. The three horizontal arms need to be attached to the motor’s pulley. You may glue them to the motor or use a little piece of plastiline to attach them firmly. You may also opt to solder the arms to the end of the tripod.

Measure and cut 24 cm (9.5 inches) of 20 gauge wire; bend the wire at the middle and turn it once around the motor´s pulley; spread out the two ends of the wire so that they are 120 degrees apart from each other; Measure and cut a piece of wire 15 cm (6 inches) long and thread it around the pulley and the other two wires; leave 12 cm (4.7 inches) of this wire on one end; now, set the wire apart so that the three wires are at 120 degrees apart from each other.

Anemometer
Anemometer | Source

Now it’s time to attach the cups to the three horizontal arms. Mark the polystyrene cups with the blue marker in half and cut them with the scissors.

Mark the center of the cups with a blue cross.

Bend one cm (0.3 inches) of each end of the three wires; this will help hold the orifices of the cups horizontally; with a piece of black masking tape, attach each end of the three wires to the center of the cups.

How Does an Anemometer Function?

An anemometer may consist of three or more hemispherical cups assembled on a vertical shaft. The difference in wind pressure causes the shaft to spin as the wind enters the cup facing the direction of the wind. When the first cup reaches 120 degrees from the point at which it was pushed away by the wind, the second cup takes its place, and is filled with air and pushed away in the direction of the wind. When the second cup reaches 120 degrees, the third cup takes its place and the cycle is repeated.

The three horizontal arms in the anemometer will continue spinning as long as there is wind blowing in the environment. As the wind blows, the cups will rotate and the stronger the wind blows, the faster the cups will rotate, The number of spins in an anemometer are used to calculate the speed of the wind.

When the wind blows on an anemometer, the anemometer spins at the same speed as the wind. The speed at which the cups revolve around the axis may be measured in revolutions per minute (rpm) or in meters of feet, depending on your measuring preferences.

How to Calculate the Speed of the Wind in an Anemometer?

To calculate the speed of the wind in miles, measure the distance the a cup, that you should have already marked, travels once around the anemometer’s axis. You can do this by measuring the circumference that the three cups make while they spin around the axis. Measure the radius of the circumference by measuring the distance of one of the arms from the axis; double that distance and then multiply that distance by π.

r x 2 x π = C.

Count the number of times the marked cup revolves around the axis in one minute; multiply the number of turns by the circumference. this will give you the speed of the wind in inches in one minute. Convert this to miles by dividing the number of inches by 12 to obtain feet and then, divide that result by 5,280 to obtain miles.

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