We call sensor yet device that automatically measures a variable, such as temperature, pressure or even speed, among other things .
An interesting point to keep in mind is that Thanks to the information that a sensor gives us as a result, we can deduce other variables that are not precisely the ones it is measuring. This example illustrates this: all the information that a flow meter gives us (it is an instrument used to measure the flow rate of a fluid or what is called mass flow rate) of hot wire is, in short, the electrical energy that is needed for a metallic thread is kept at a certain constant temperature. With the information we receive we can deduce the mass of air that circulates around that same thread. This example is also applicable to many other sensor cases, as described for the equipment used for the determination of oxygen pressure in arterial blood; In the laboratory test popularly called "blood gases", two sensors detect oxygenation and carbon dioxide pressure, allowing indirect calculation of numerous associated parameters.
The sensors, basically, transform or reproduce a certain physical phenomenon (they can also be chemical or physicochemical) into a "signal" that can be a unit of measurement (as in the case of thermometers or barometers), into sounds (such as alarm security systems) or in specific actions (for example, when we open the door of an ATM by entering a magnetic card). This process is known in the field of science as transduction, which constitutes the conversion of data into information in a different "language". Thus, a classic mercury thermometer is based on the expansion of the liquid metal in a column, which motivates its displacement along a graduated rule: the "data" arises from the expansion, the "information" is the temperature and the " transducer "is the quantized column.
Another well-known and commonly used example is the sensors used in alarm systems, which are installed in businesses or homes as a way to provide security to property in cases of robbery or assault. The motion sensors used in these cases allow the entry or movement of a person to be detected in one or more areas of the home or business, once we have activated the alarm security system.
There are other devices with sensors that are used to notify people entering or leaving a property. In this case, they are small devices that are installed in doors, and when this is moved, they are activated producing a specific sound. These devices are always active, and there is no way to deactivate them when we do not want them to function (except to uninstall them from the place where they have been set). An analogous system is used by elevators and forklifts, known in the jargon as "electronic eye", since it recognizes the presence of people at the door to prevent its automatic closing and, thus, minimize the potential risk of accidents. The sensors weight in these elevators are a more sophisticated example, but with the same concrete utility.
To speak specifically about the automobiles we will say, for example, that the proximity sensor It is one that can detect people, cars or other objects. The most common sensors The proximity devices used are: ultrasound, near and far infrared, visible light camera, etc.
Although they are precisely called sensors because they "feel" or capture some condition that allows them to function for what they have been designed, a new branch of sensors are those of Wireless Network, that is, wireless connections (without the use of cables) for its activation and operation. In this case, you can also measure temperature or humidity, for example, but instead of using thermometers or barometers for this, it is computerized sensors and connected to a computer network that allows you to transform their variations into electronic signals. The initial technology for these sensors It was applied in space shuttles, but today it is part of various equipment used on a daily basis. In fact, modern touchscreens are an interesting example of everyday, dual sensors, that is, they not only "sense" data for processing, but they "return" information. Consequently, the most current sensors are bi-directional utilities, since they can effect transduction in one direction or the other.
Finally, in biological sciences, we cannot forget that the sense organs act as sensors, either unidirectional (vision, smell, hearing) or bidirectional, as occurs with the skin. Internal sensors that detect the spatial position of each organ and system provide the nervous system with the information necessary for the preservation of balance, control of movement and interaction with the world around us.
