The 12 types of sensors: their characteristics and functions

This object allows to detect movements or other inputs. We explain what types of sensors exist.

Do you know what a sensor is, what it is used for, or how it works? In this article, in addition to answering these questions, we will talk about 12 different types of sensors. As we will see, these vary depending on the type of variable they measure or detect.

In addition, we will explain their general characteristics, what they are used for, how they work, and we will mention some examples of them.

What is a sensor?

Before explaining the different types of sensors that exist, let's see what a sensor is. It's probably a concept you may be familiar with from physics, or even chemistry. But what exactly is it?

A sensor is a device or an object that has the ability to capture different stimuli from the outside, and to transform them by means of a transducer into electrical energy (electrical impulse).. In other words, it transforms (or translates) information or energy from the outside into an electrical impulse (usually a digital impulse). This external information can be of any type (physical, chemical...).

Subsequently, these impulses are analyzed, processed and transformed, in order to generate a certain response. We can find different types of sensors, as we will see below.

Types of sensors

Thus, we find different types of sensors, depending on the type of variable to be measured or detected. In this article we explain what are the 12 types of sensors that we can find, how they work and some examples of them.

Temperature sensor

The temperature sensor provides us with information on the temperature of the outside (i.e. the medium) by means of electrical pulses. (i.e. of the medium), by means of electrical impulses. These sensors make it possible to control the ambient temperature.

Temperature sensors are actually resistors, whose value increases or decreases with temperature. In the first case, we call them PTC thermistors, and in the second case, NTC thermistors.

In turn, temperature sensors can be of different types: contact, non-contact, mechanical and electrical. An example of a temperature sensor is a thermometer (the classic mercury thermometer) (in this case, it is a mechanical sensor). This type of sensor is especially used in the industrial sector; its purpose is to control the temperature of different machines, among others.

2. Light sensors

Other types of sensors are light sensors; in this case, These are electronic devices that respond to changes in light intensity, i.e. they can determine the presence of light..

In other words, they can determine the presence of light. Thus, this type of sensor detects visible light (i.e. the light that we perceive with the eye), and also responds according to its intensity.

An example of a light sensor is the photoelectric cell, a device that transforms light energy into electrical energy through an effect known as the "photoelectric effect". This device makes it possible to generate photovoltaic solar energy.

3. Distance sensors

Distance sensors are devices that can measure distances and, depending on the type, they can also be used as presence sensors or as sensors of the presence or absence of a person, Depending on the type, they can also be used as presence or motion sensors..

An example of a distance sensor is the infrared sensor, which is based on a system of emission and reception of radiation. We also find, as an example of a distance sensor, the ultrasonic sensor, which sends pulses causing the waves to bounce off the surface.

4. Proximity sensors

The following types of sensors, proximity sensors, consist of transducers that detect the presence of objects (obstacles, people, etc.) without the need for (obstacles, people...) without the need for contact. In some cases they can also be configured to measure distance.

5. Position sensors

Position sensors allow us to determine the location of an object.. As a characteristic of them, we find that they generally have a particular electronic system, so that they can determine the location with maximum precision.

6. Color sensors

Color sensors convert light into frequency, in order to be able to detect the colors of certain objects from their reflected radiation.They compare these radiations with the stored reference values.

These types of sensors emit three types of light: red, green and blue, and do so on the objects they intend to analyze. Finally, these devices generate an output signal (a response).

7. Humidity sensors

These types of sensors measure the relative humidity as well as the temperature of the environment. Specifically, they act by emitting a conditioned signal, thanks to a series of integrated circuits they have.

Humidity sensors pick up signals from the environment to detect these parameters (humidity and temperature).. In addition, their margin of error is usually very small.

On the other hand, as an example, this type of sensors can be applied to detect the level of liquid in a tank; they are also used in garden irrigation systems, in order to determine when plants need watering and when they do not.

8. Speed sensors

Also known as "speedometers", speed sensors are used to detect the speed of an object (usually a vehicle)..

An example of this is radar, which detects if a vehicle is going faster than the permitted speed.

9. Sound sensors

The following types of sensors are the sound sensors; they are in charge of capturing the sounds of the exterior (environment), through a microphone or a microphone.The sound waves received by these sensors are received by a microphone or a sonar system.

The sound waves received by these sensors propagate through the air of the environment and are then detected by the sensors.

They are normally used to receive stimuli from the outside in the form of commands (from people), remotely.

10. Contact sensors

The purpose of contact sensors is to detect the end of travel of mechanical components (or in other words, their limit position).. An example of these are: doors that open automatically, and when they are already fully open, the motor that drives them "knows" that it must stop.

11. Optical sensors

In this case, these types of sensors can detect the presence of an object (or a person) that interrupts a beam of light reaching the sensor.

An example of these (and the main ones) are the so-called "photoresistors" (also called LDR).. LDRs are used especially in robotics, in order to regulate the movement of robots and to stop their movement as soon as they are about to collide with another object.

12. Magnetic sensors

Magnetic sensors act by detecting the magnetic fields caused by electric currents or magnets..

An example of these types of sensors is the Reed switch, which consists of two metal foils inserted inside a capsule; these foils are in the presence of a magnetic field, and attract each other (i.e., close the circuit).

Bibliographical references:

• Brindley, K. (1988). Sensors and Transducers. Heinemann Newnes.

• Norton, H.N. (1989). Handbook of Transducers. Prentice-Hall.

• Pallás, R. (2003). Sensors and Signal Conditioners, Ed. Marcombo.