What an outdoor weather station does
Weather stations, also known as Weather Stations or “outdoor” weather instruments, provide meteorological data such as temperature, humidity, atmospheric pressure, and rainfall. They can be used for different public services (weather forecast), education, or personal usage. All outdoor weather stations consist of a compact unit attached to the roof of a house or building without causing any discomfort to the inhabitants.
The equipment contains typically:
a) A Sensor: It measures physical phenomena and sends them by wire (copper wiring) up to the display unit using electricity.
b) A Display Unit: This part consists of two main components; a transmitter and a receiver. The data measured by the sensors is sent from the transmitter to the receiver, where the information is processed and given as an output.
c) An Indoor Unit: The indoor unit consists of a self-contained display device designed to be placed anywhere indoors within a building. This part doesn’t have any wiring or power supply as it gets all its power from batteries or from being plugged into the mains electricity supply.
d) External Accessories: Additional equipment can be acquired separately, such as data loggers, remote sensors for outside measurements, etc., which increases the functionality of the weather station by providing additional information about conditions outdoors.
e] Sensors: Several types of sensors measure different physical phenomena to give an accurate picture of atmospheric conditions in various locations. These are used to measure air temperature, humidity, rainfall, barometric pressure, and wind speed. Temperature is measured by a thermometer with a sensor that consists of two parts; one part is placed outside near the measuring device while the other remains inside where the display unit is placed. The most commonly used machines for this process are mercury-in-glass thermometers or solid-state sensors in wireless digital outdoor units.
Sensors that measure humidity are typically called psychrometers and consist of two thermometers whose temperatures are very close but have different sensitivities to moisture. One is kept dry while the other is exposed to the surrounding air to evaporation on it. The difference between its temperature and that of the dry bulb indicates how much water vapor is in the air. The most common type of rainfall sensor uses a rotating impeller that spins due to the gravitational force when it is facing downwards towards the ground. An electrical contact breaks as soon as this happens, causing electricity to flow through the coiled wire, creating resistance and producing voltage pulses representing each impeller’s rotation. This type of sensor can be used for various purposes, such as irrigation or collecting rainwater.
Barometric pressure sensors are usually mercury-in-glass barometers with an added gear mechanism that rotates electronic contacts every time there’s a change in atmospheric pressure. An electromagnet attached to these contacts actuates a reed switch that produces pulses proportional to the number of clicks per unit time. Pressure changes are usually minimal, and the speed (frequency) of these pulses is measured by the microcontroller, which converts them into a digital value that can be displayed. Wind sensors measure the effect produced by the wind on an object, such as vane type, ultrasonic, or hot-wire anemometers.