the fast paced world we live in today, there is a high demand for increased
automation in systems that concern our businesses, industries and everyday
life. The Internet of Things also known as IoT devices provides a perfect
solution to this problem by its ability to collect, analyse, respond to and
transfer or share large amounts of data, all of these often carried out without
the need for any form of human interaction or interference.
devices carry out these functions by means of sensors embedded in them. Sensors
are devices that have the ability to detect or measure certain physical
properties or conditions in the environment, collect the data present, indicate
them, transfer them for additional processing or internally analyse and respond
to them. The data collected by these sensors is used to make informed decisions
about certain environmental conditions, systems and/or processes and
Internet of Things (IoT devices) is a wide range of automated machines and
electronic devices integrated for use in our everyday life, businesses,
industrial work and so on. As the need for this sort of devices increase, many
more sensors are utilized to aid in the collection, analysis and exchange of
of IoT Sensors
type of function a device is designed to carry out would determine the type of
sensor it utilizes. For optimum effect, some devices consist of more than one
sensor. Sensors are designed to be sensitive to physical conditions such as
heat, light, pressure, or the presence or absence of specific conditions like
gas or water. They have the ability to detect these conditions, measure their
magnitude or impact and transfer the data acquired by means of electrical signals.
Some commonly used sensors are pressure sensors, proximity sensors, temperature
sensors, optical sensors, infrared sensors, level sensors, motion sensors,
image sensors, humidity sensors, water quality sensors, chemical sensors, gas
sensors, smoke sensors, acceleration sensors and gyroscopic sensors. Below is a
general description of each of these sensors as used today.
pressure sensor is a device that can detect and measure the pressure of a
liquid or gas expressed in force per unit area. It transforms pressure to a form of electrical signal or
wave which it indicates and shares. The most types of pressure measured by
these sensors are Gauge pressure, Absolute pressure and Differential
sensors are used to detect the presence of a nearby object without actually
touching it. They do this by emitting a beam of electromagnetic energy or an
electromagnetic force field into the surrounding environment and then they
detect changes in the beam on its return. The most common types of proximity
sensors are capacitive, inductive, photoelectric and ultrasonic proximity
sensors. They are differentiated by the
medium through which they detect the presence of nearby objects.
sensors determine the temperature level of an environment or object and convert
the data to an electrical signal which can indicate the exact temperature
value. They are used widely in agriculture to determine and maintain the right
temperature for good crop yield, industrial processes, amongst other functions.
examples of temperature sensors are thermometers, thermocouples, thermistors,
sensors are used to detect the presence of light in an area. They are able to
convert light rays into electromagnetic signals that can easily be read and
understood. They work in two ways:
- By sensing the interruption of
a beam of light by an object or
- By sensing the reflection of
that beam of light by the object.
they can also be used to detect the presence of a nearby object. There are
three basic types of optical sensors namely Through-beam sensors,
Retro-reflective sensors and Diffuse Reflection sensors. Each of these optical
sensors works differently and can be applied in different ways. Generally,
optical sensors are used in the mining industry and chemical factories and
sensors are used to detect and measure the amount of infrared radiation emitted
by an object or in an area. Some IR sensors also emit infrared radiation into
an environment in order to detect changes in certain environmental or physical
conditions. They can be used to detect and measure the heat emitted by an
object, detect motion and measure distance, all without having close contact
with the object. In the health sector, they are used to determine and analyse
the blood flow and blood pressure of patients. They are also used in gas
detection, determination of water quality, climatology, night vision, etc.
are sensors that measure the level or quantity of a liquid or fluid substance
in relation to a normal benchmark value, and then convert the data required
into a signal that can easily be understood. They are found mostly in
automobiles where they are used to provide the driver with information on the
quantity or level of fuel in the fuel tank via the fuel gauge. Some vehicles
even have indicator lights that go off when the fuel level is very low to alert
the driver to the fact that the fuel tank is almost empty.
sensors are used to detect the movement of a physical object. They are used
widely in security systems to alert property owners to any strange movement on
their property. They are also used in the automation of devices and appliances
such as air conditioning and heating systems, showers, control of doors, etc.
major types of motion sensors are Ultrasonic motion sensors, Passive Infrared
(PIR) motion sensors and Microwave Detection motion sensors.
sensors are sensors used to take images that are stored digitally for future
processing. They can also detect images stored previously. Image sensors are
commonly used in facial recognition systems and are also used to capture
licence plate numbers, etc. They can be found in smartphones, licence plate
readers and other systems that require high quality imagery and storage.
sensors are used to detect and measure the humidity of air and other gases in
an area. The data collected are used in industrial and chemical industries and
processes that require controlled environmental or physical conditions.
quality sensors are very important in the control and maintenance of certain
factors and parameters that affect the quality of water. This is especially
important because water is used for everyday activities like cooking and
drinking and other industrial processes, and a change in the quality of the
water can create adverse effects.
determining water quality, these sensors take the following into consideration:
- Chemical presence or levels
- Oxygen levels
- pH level
- Electrical conductivity, etc.
sensors are used to detect the presence and quantity of certain chemical
substances in a space. They are commonly used in chemical industries and
refineries to control leakages and provide good safety conditions for workers.
are similar to chemical sensors highlighted above. They are used to detect the
presence of combustible and toxic gases in the air, especially those that
cannot be easily detected by man’s ordinary senses. Examples of gases that gas
sensors can be used to detect include Carbon monoxide (CO), Hydrogen (H2),
Hydrogen Chloride (HCl), Bromine (Br2), Formaldehyde (HCHO), Ozone
(O3), Hydrogen Peroxide (H2O2), etc.
sensors are used to detect the presence of smoke in an environment. They are
used commonly in fire alarm systems to prevent and curtail fire outbreaks. The
two major types of smoke sensors are the Ionization smoke sensors and the
Photoelectric or Optical smoke sensors.
sensors are also known as Accelerometers, and they are used to detect and
measure the linear velocity of an object or its change in speed over time.
There are several types of acceleration sensors and their application depends
on the conditions surrounding the change in the rate of velocity. They are
Half-effect acceleration sensors, capacitive acceleration sensors and
Piezoelectric acceleration sensors.
Also known as Gyroscopes, these sensors are used to detect
the rotation of an object around an axis and measure its angular velocity. They
differ from accelerometers by their ability to calculate the velocity of an
object in relation to the earth’s gravitational pull. Gyroscopes are used in
airplanes and the aviation industry in general.
stated earlier, these sensors are integral parts of devices used in several
areas of life. They contribute significantly to the advancement of automation
in the world today.