Weather station
La Crosse (WS-2355)
The station is a wired system with dispersed sensors.
The wind vane and speed sensor are located about 10 metres above average ground level.
The rain gauge is, unfortunately, not located a foot (300mm) or so above ground level, but about 3 Metres.
The temperature and atmospheric pressure sensors are about 3 Metres above ground level (not ideal) but are in a position where the sun never shines.
|
|
Describe the outdoor thermometer, if you have more than one sensor, include information about all. |
|
Describe the outdoor humidity sensor, if you have more than one sensor, include information about all. |
|
A pressure sensor is usually called a barometer. There is a number of types of barometers. Most household barometers are of the 'aneroid' type - they are the type which rely on the reshaping of a metal container due to outside pressure (and often need at tap to coax the mechanism along). This station uses an electronic version. In this there are no mechanical moving parts but it still relies on a sensor all the same, obviously. Like many bathroom and kitchen scales this uses a tension unit. Whilst it may not be quite the same as those I suspect, though cannot confirm, that it uses the piezoelectric effect. Basically this means that the behaviour of the electrics (current flow and voltage) vary depending upon the pressure applied to a particular construct. |
|
The station's wind speed sensor is simply a series of magnets positioned at sixteen points around a circular vane (see later) holder. This uses the Hall Effect and can be quite accurate within its construction. What's a Hall Effect? Well, in essence, it's the production of an electric current as a magnet passes another magnet.
The station's speed sensor consists of a number of 'cups' which, regardless of the direction of the wind, spin because of the wind pressure. This comes about because the 'open' end of each cup is wider than the other side of the cup, which is 'streamlined'. This speed sensor has three 'cups' space 120º apart. |
|
The direction sensor is no different to the weather vane seen on the top of buildings. The only difference is that it uses magnetic influence in order to report in which direction it is pointing. Otherwise, apart from the fact that it is merely a pointer with a tail, the station's vane is no different from the plethora of wind vanes you might have noticed over the years, including the ROOSTERS. :) |
|
A 'self-tipping' rain gauge is employed at the station. If you haven't seen one, it consists of a 'see-saw' with a peak above the pivot point. At the end of each 'arm' of the see-saw is small cup which collects the precipitation. When the cup is full the design of the unit causes it to drop. Because of the pivot point peak this causes any further incoming rain to flow to the other cup. The size of the cup and the collection area of the gauge defines the limit of each "'tip's" accuracy. |
|