There are different types of sensors used to translate the information coming from outside into an electrical impulse. This impulse usually passes to a control unit where it is analyzed and transformed in order to generate a reaction or response.
The information that arrives from the outside to any sensor is a physical or chemical stimulus that, internally, is translated into an electrical quantity. Sensors emulate the sensory system of human beings In this way, different machines use sensors to interact with the environment that surrounds them.
Light sensor
A sensor is also used to obtain information about the environment. In this way, a thermometer is a sensor that provides numerical information about the temperature of a given environment.
Many times we use sensors to generate responses that facilitate the performance of daily activities. Sensors today are part of our daily lives. We are in permanent contact with different types of sensors that help to facilitate day-to-day tasks.
In this way, automatic power plants, solar panels, our smartphones, and other devices are equipped with sensors that help us interact in a better way with the environment.
Main types of sensors
There are multiple types of sensors whose function varies according to the type of stimulus they can detect.
Ultrasonic
They are sensors used to detect the physical proximity of an object in order to avoid friction or mechanical shock.
They operate by sending out a sound wave, which subsequently hits a surface and bounces back. In this way, the sensor measures the time it takes for the wave to return and thus calculates the distance between objects.
It is a type of sensor that works only in spaces where there is presence of air, since the displacement of the sound wave can only occur in this medium.
On the other hand, it is useful for detecting objects regardless of their state (solid or liquid) or their color, therefore, they are excellent for tracking or distance measurement tasks.
Humidity
They are sensors that measure the relative humidity and temperature of an environment. They have integrated circuits that allow them to emit a conditioned signal.
They usually have a sensitive point that captures signals from the environment. This point is manufactured with polymers and platinum electrodes.
Most are laser calibrated, perform well, and have a minimal margin of error.
Speed
The sensors used to detect the speed of an object or vehicle are known as "speedometers."
There are different types of sensors to detect speed, such as wheel sensors, vehicle speedometers, LIDAR (by its English name "Light Detection and Ranging"), ground speed radars, Doppler radars, speed indicators, pitot tubes, among others.
These sensors are often used for engine timing in different industries. They are also useful for controlling the speed or revolutions per minute of a given machine.
On the other hand, on the roads it is common to see speed sensors whose task is to detect the speed of the vehicles that travel on said road.
Temperature
A temperature sensor is a device that provides information about the temperature of the medium through an electrical impulse. This electrical impulse passes in the form of voltage, and the proportion of this voltage is equivalent to the value of the measured temperature.
There are different types of sensors used to measure temperature. There are contact sensors, non-contact sensors, mechanical sensors, and electrical ones.
An example of a mechanical sensor is a conventional thermometer and an electrical sensor can be a thermistor.
Temperature sensors are used in the industrial environment to monitor the temperature of appliances and machines involved in manufacturing processes. In this way, the information taken from the environment can be read and controlled.
Pyroelectric
A pyroelectric sensor or PIR sensor is one that is used to measure the radiation of infrared light emitted by an object within its field.
Every object that has a temperature above zero degrees produces heat energy in the form of radiation. This radiation emits infrared waves that are invisible to the human eye, but can be picked up by PIR sensors.
PIR sensors are classified according to their angle (the width of the area they can cover) in relation to the number of moving elements they can detect within that area.
They are sensors commonly used in everyday applications, such as the automatic door opening system and in general all systems that react to movement.
When a body moves, an infrared signal is emitted. When this signal is detected by a PIR sensor, it sends a signal to a microcontroller, which will be in charge of translating said signal into a response.
Light
Light sensors are reflective sensors that operate by interception of the signal. They operate by making use of a receiving cell for the stimulus sent by a light source, which can be a lamp, an LED, a laser diode, among others.
There are many types of photo-receptor cells, each of these types reacts according to the intensity of the light signal received. Generally, the light signal can be converted into electrical energy, by being captured by photovoltaic cells.
This is the case with solar panels, which capture the free electrons present in sunlight, and transform them into an electrical current that can be used to power a circuit.
Contact
Contact sensors are those that use switches that are activated using physical actuators.
Some industrial robots use this type of sensor in the form of "cat whiskers" or fine wires that allow them to detect the proximity of the elements.
Contact sensors are useful to avoid bumps between objects. For this reason, they are commonly used in the automotive industry on the rear bumpers of cars.
Sound
This type of sensor has the ability to capture sounds from the environment through a sonar or microphone system. They are usually used to receive stimuli as commands remotely or to measure distances based on the perception of the sound wave.
Sound sensors work in a similar way to ultrasonic sensors in that the sound wave must travel through the air in the medium before it can be detected by the sensor.
References
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- Olivia, JE (December 10, 2010). Obtained from CLASSIFICATION OF SENSORS: thelastlabproject.blogspot.com.br
- Porto, JP, & Gardey, A. (2010). of. Obtained from SENSOR: definicion.de
- Sensors and Transducers. (2017). Obtained from Types of Sensors: profesormolina.com.ar.