Sensors are extensively used in numerous electrical appliances throughout the world. They strive to make our lives simpler by performing many jobs such as turning on the lights when we walk in the room, detecting smoke or fire, regulating the room temperature, making us a great cup of coffee, opening garage doors, etc. This article will dive into the specifics of what a sensor is, the applications of sensors, as well as the different types of sensors available.
What is a Sensor?
A sensor is a device that takes physical input from its surroundings and turns it into data that a human or a machine can evaluate. The majority of sensors are electronic, however, some can be analog. For example, a glass thermometer that displays body temperature is an analog sensor.
Types of Sensors
Sensors are categorised depending on their function. Some common types of sensors include:
A temperature sensor is one of the most commonly used sensors. As the name implies, this sensor detects the temperature as well as monitors temperature changes. Temperature sensors come in a variety of forms, including temperature sensor ICs (such as the LM35 as well as DS18B20), thermistors, thermocouples, RTDs (Resistive Temperature Devices), and so on. These sensors can be either analogue or digital in nature. Temperature variations in an analogue temperature sensor correspond to changes in physical properties such as resistance or voltage.
A variety of electrical appliances like computers, automobiles, mobile phones, air conditioning systems, etc, use temperature sensors. Another common practical use of a temperature sensor is in an industrial temperature controller, used for managing the temperature of devices employed in manufacturing companies.
This type of sensor is a sort of non-contact sensor that detects the presence of an item in its vicinity. To do so, proximity sensors employ a variety of approaches such as optical (such as infrared or laser), sound (ultrasonic), magnetic (Hall Effect), capacitive, and so on. The different applications of proximity sensors include parking sensors, object alignment in industries, as well as ground proximity detection in aircraft. Another common application of these sensors lie in automatically shutting and opening doors. These doors close and open depending on body movement near it.
Infrared (IR) Sensor
IR sensors, also known as infrared sensors, are light-based sensors, utilised in a variety of applications such as proximity and object detection.
Infrared sensors are classified into two types: transmissive and reflective.
- A transmissive type IR sensor can detect an object that passes in between it and a detector placed opposite to it.
- A reflective IR sensor detects an object that passes in front of the sensor. Here, the detector is placed next to the sensor.
IR sensors find many applications in robots, mobile phones, industrial assembly, vehicles, and many more.
An ultrasonic sensor is a non-contact device that can measure the distance as well as the velocity of an object. It operates on sound waves at frequencies higher than the human auditory range. The sensor can detect the distance of an item by measuring the duration of the sound wave. Furthermore, using the Doppler Shift feature of a sound wave, an ultrasonic sensor can calculate an object’s velocity. People may also use ultrasonic sensors to measure distances in regions with difficult and hard to traverse terrain.
Photo sensors, also known as light sensors, are essential for many devices. One example is the Light Dependent Resistor or LDR. The resistance of LDR is inversely proportional to the intensity of the ambient light, which means that as the intensity of light grows, so does its resistance, and vice versa. Thus, we can calibrate variations in the resistance of an LDR in a circuit to estimate the intensity of light. A photo-diode and a phototransistor are two other light sensors that are frequently utilised in complex electrical systems. These are types of analog sensors.
Smoke and Gas Sensor
A smoke and gas sensor is extremely valuable in safety-related devices. In fact, almost all homes, workplaces and companies have smoke detectors, that detect any smoke caused due to a fire and sound an alert.
On the other hand, labs, large-scale kitchens, and industrial settings commonly have gas sensors. They can detect various gases such as LPG, Propane, Methane, Butane, and others. For example, the “MQ” series of sensors is a collection of low-cost sensors for detecting carbon dioxide, carbon monoxide, methane, butane, propane, alcohol, and other gasses. These sensors can be used in a DIY smoke detector.
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