Please, how can we find the sensing coverage/sensing range of different sensors (and if any, the wider range of sensing also but with degradation in the sensed value due to distance) to determine the number and places of sensors such that a monitored area is fully covered.

This for sensor for different phenomena such as: temperature, relative humidity, pressure, light intensity, soil parameters, CO2 , etc.

Thank you.

 

A pretty open ended question really. The phenomena you state relate well to plant growing. It is well known that, even though an area may have general conditions, the area around specific groupings may be subject to microclimates in which conditions do vary greatly from the norm. This does mean that, although any area does have general figures that may be measured, spots checks may give massive differences. When these type of figures are measured for weather forcasting etc, the measuring equipment is placed in such a position so local effects like vegitation and buildings have minimal effect.

Tracy

 

To elaborate on the response by @BBee...

The way you have asked the question makes it difficult to answer. If you think about the problem a little bit differently, it might be helpful.

Although you have not mentioned specific sensors except by category, basically, the types of sensors that you have mentioned only measure the characteristic in their immediate environment. More accurately, they are transducers with no “range” at all. They are contact sensors. The sensor is sensitive to the characteristic only at the precise location that the sensor occupies. They are not designed to measure anything at a distance (ignore for the discussion non-contact sensors).

Understanding that, you can rephrase the question as “how representative is the sensor’s output to a larger area. Of course, that is going to depend on how variable the characteristic is over the entire area and how representative you need it to be for a particular purpose. Therein lies a bit of a conundrum as you need to employ multiple sensors to estimate the variability of the property that you are sensing across the entire area. The more sensors that are distributed over the area, the better the estimate.

Moreover, it is usual, but not necessary for discussion, that you also want to control the property that you are sensing.

It is situation specific and I am unaware of any standardized formula that exists to determine how many sensors are required because, again, it all depends.

In practice, one might, somewhat arbitrarily, divide up the space into zones and place one sensor in each zone. In the case of a house, only one temperature sensor in the living room might be used. In another case, one sensor in each room might be used. In the case of a 1000 cubic feet growth chamber, 10 temperature sensors might be used. In another case, a typical weather report will provide temperatures in various populated municipalities across a much larger area.

If you consider the property of atmospheric pressure, for example, it is may be a very different practical situation, but the strategy of defining a zone and estimating the variability of the characteristic across that zone, remains.