The types of sensors, which are current technology’s inventions that make living easier, now appear at every moment in our daily life. Sensor technology is increasingly being utilized to control the television remote, turn on the apartment lights, open and close automatic doors, and more and more for the action that has become part of everyday life. That is how crucial the sensors are that we use on a daily basis without even realizing them. So much so that if sensor technology disappeared from our lives today, severe issues in the natural flow of life would develop.

In this article, we will try to answer the questions “What is sensor?”, “How do the sensors work?” and “What are the types of sensors?” briefly.

What Is Sensor?

Sensors are devices that detect changes in electrical, physical, or other quantities and produce an output as a confirmation of that change. Usually, this sensor output is in the form of an electrical or optical signal.

Sensor technology is defined as a technology that detects and converts physical quantities such as force, pressure, voltage, and light into the desired output, such as an electrical signal, in order to measure the physical quantity applied. In some cases, a sensor alone may not be sufficient to analyze the resulting signal. In these circumstances, a signal conditioning unit is also utilized to keep the sensor’s output voltage levels within a certain range.

In a signal conditioning unit, the output of the sensor can be increased, filtered, or changed according to the desired output voltage. Signal conditioning may not be necessary for sensors such as photodiode and LDR. Most sensors are unable to operate independently. Therefore, the sensors should be given sufficient input voltage. Some types of sensors have different operating ranges that should be considered when using them. Otherwise, the sensor may be permanently damaged.

How Do Sensors Work?

The principle of operation of the sensor is based on its response to changing physical conditions by changing its electrical characteristics. That’s why most artificial sensors collaborate with electronic systems to capture, analyze and transmit environmental data. These electronic systems operate on the same principles as electrical circuits. Therefore, it is critical to manage the electric current. Simply put, a sensor converts inputs like heat, light, sound, and motion into electrical impulses. These signals are passed through an interface that converts them into binary code before transmitting them to a computer to be processed.

Due to the principle of operation of the sensor, many sensors act as a switch that manages the flow of electrical charges throughout the circuit. Switches are essential components of electronics as they alter the state of the circuit. Sensor components such as integrated circuits, transistors, and diodes all contain semiconductor material and are included in sensor circuits to act as switches.

Types of Sensors

The most commonly used types of sensors are classified as electric current, potential, magnetic, radio sensors, humidity sensors, flow sensors, pressure sensors, heat or temperature sensors, proximity sensors, and optical sensors.

Mechanical Sensors

Mechanical sensors are sensitive to changes in mechanical properties. Along with micro-processing technology, mechanical sensors including consoles and acoustic sensors, play a key part in molecular detection and other biomedical practices. Optical or other electrical measurements are also important in certain situations.

Inductive Sensors

Inductive sensors are used to detect metals. They are often used in harsh environments because they are very robust and can provide stable signals even in difficult conditions. Inductive sensors detect it when a metal object approaches the magnetic field within the sensing distance. The sensor generates an output signal based on the metal object affecting its magnetic field. Inductive sensors are used in metal detectors.

Photoelectric Sensors / Optical Sensors

Photoelectric sensors, also known as optical sensors, are electrical devices that can detect color, cleanliness, and position as necessary, but they frequently detect objects passing through the sensing area. Optical sensors detect changes in fiber optic detection, temperature, voltage, and other characteristics by observing the physical properties of light as it travels through a fiber line. The principle of operation of these sensors is based on the measure changes in the reflection of light emitted by the sensor which uses a transmitter and a receiver. Photoelectric sensors are used for counting, robotic collection, and opening/closing the power-operated doors, etc. They’re also widely used in production and material transport automation.

Analog Sensors

Sensors that produce continuous analog output signals are referred to as analog sensors. This continuous output signal generated by analog sensors is proportional to the measured size. Some types of analog sensors include accelerometers, pressure sensors, light sensors, sound sensors, temperature sensors, etc.

Accelerometers

Accelerometers are analog sensors that detect motion and changes in location, speed, direction, shock, vibration, and inclination. These analog accelerometers are categorized into classes according to the variety of configurations and sensitivities. They are also divided into analog and digital sensors based on the output signal. The analog accelerometers produce a constant variable voltage depending on the amount of acceleration applied to the accelerometer. Accelerometers are often used in a variety of applications, including the automobile industry and wireless gaming consoles.

Light Sensors

Analog sensors used to detect the amount of light reaches sensors are called light sensors. These analog light sensors are divided into various types such as photo-resistance, cadmium sulfur (CdS), and photocell. Light sensors detect the amount of light using light-sensitive resistance (LDR). The resistance of the LDR increases as the light level decreases and decreases as the light level increases. These sensors are automatically used for turning lights, blinds, or curtains on and off according to the daylight in the environment. Light sensors are a must for smart homes.

Sound Sensors

Analog sensors used to detect sound levels are called sound sensors. These analog sound sensors convert the amplitude of the acoustic volume of the sound into an electrical voltage to detect the volume. Sound sensors use a microcontroller along with a microphone to generate an analog output signal.

Pressure Sensors

Analog sensors used to measure the amount of pressure applied to the sensor are called analog pressure sensors. The pressure sensor generates an analog output signal that is proportional to the amount of pressure applied. 

Temperature Sensors

Temperature sensors are divided into digital and analog sensors. Thermistors are analog temperature sensors that are commonly utilized. There are different types of thermistors used for different purposes. A thermistor can detect changes in temperature by the decrease or increase of the resistance coefficient through heat. The electrical resistance of the thermistor increases as the temperature increases. The resistance decreases as the temperature decreases. Temperature sensors used in devices where instantaneous temperature value is important, such as thermostats, air conditioners, ovens, etc.

Digital Sensors

Digital sensors are electronic or electrochemical sensors in which data processing and transmission are carried out digitally. Digital sensors consist of three main components: sensor, cable, and transmitter. Inside digital sensors, the measured signal is converted directly into a digital output signal. This signal is transmitted digitally via cables. Digital types of sensors are gradually replacing analog sensors as they are able to overcome the drawbacks of analog sensors.