Internet of Things: Taking your environment with you

Most of us have heard about IoT, some have have experienced it while some adventurous once (like I am) have meddled with it. Just like robotics and AI are gaining popularity, internet of things is also gaining grounds in today's technology, little wonder why we see the world's most popular chip making company, Intel, creating special place for IoT.

^{[credit: pixabay. CC0 license. Author: Geralt]}

If you have ever wished to monitor your home or office while you're away, find your pet whenever its location is unknown, create special alerts in case of emergencies, tone up the security of your environment, remote control virtually most appliances in your home and office, then think internet of things.

Internet of things as a complete system has not been around for long but its framework has been around since early 1900. The first radio voice communication took place at the end of second quarter of 1900 whereas the internet which is a major component of the IoT technology itself was developed 62 years later as a result of research carried out by the the Defense Advanced Research Projects Agency (DARPA).

The discovery of GPS also followed suit 31 years later (1993) with a stable version put forward by the DoD (Department of Defense). All these communication frameworks including the commercialization of satellites provided a good communication base for the internet of things technology.

The idea behind the internet of things is to increase the relationship between man and his environment and also to provide comfort beyond measure. With IoT, you can comfortably power off electric bulbs in the house, set a desired temperature for your environment, close or open gate for an identified visitor or your fellow house occupant, set off an alarm, monitor your environment live, and the list is endless. The basic component of an IoT system includes:

Signal Transducers and Sensors

Actuators

Communication system and

Controller system

To understand how the above component relates to create an amazing system that can perform the above mentioned functions, I'll zoom in on the individual components.

Signal Transducers and Sensors

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For a system to perform the aforementioned functions, it has to be able to directly communicate to the environment. Simply put, a signal transducers is any device or component capable of converting energy between different forms. A transducer senses the environmental condition and converts such conditions into electrical signals. Hence, a transducer can be regarded as a sensor.

Both the transducer and sensor are capable of converting environmental variables like motion, light intensity, vibrations , etc., into electrical signal. Sensors differs from actuators in the sense that while sensor performs a kind of input function, actuators performs output functions. These functions are response to characteristic change in the physical environment.

A very good example of a sensor is the mouthpiece in our phones which converts physical quantity (acoustics) into electrical quantity while that of a transducer is the earpiece which converts the electrical quantity into sound.

Another example of transducers and sensors is the light dependent resistor which lowers or increases its resistivity as light rays bounces on it while its transducer counterpart is the light emitting diode which converts electrical signal into physical quantity (light).

Conditioning Transducers and Sensors

Sensors generate electrical signal that is directly proportional to the physical quantity they are quantifying. This generated electrical signal is dependent on the type of sensor in use but sensors are broadly classified as either passive or active. When a sensor is of the active type, it means that the sensor requires an excitation (external power supply) to be able to produce an output.

However, when a sensor is of the passive type, no excitation power is required to produce an output from the sensor, hence, an active sensor changes its own electrical properties in response to an external stimuli while a passive sensor generates an electrical signal in response to an external stimuli.

No matter the type of response generated from sensors, these signal are not pure enough to be processed directly by electronic circuits. Hence amplification and filtering are required to amplify and purify signals picked up from the environment in the case of sensors, while amplification and purification are also necessary when sending signals to the environment in the case of transducers.

^{[A non inverting Opamp configuration. Credit:wikimedia. CC0 license. Author: Inductiveload]}

The operational amplifiers are usually one of the best component when choosing amplifiers for very weak signals. The Opamp as it is fondly called has two major amplification configuration which are the inverting and the non inverting configuration. The two configurations are named depending on terminal of the opamp the input signal was connected to. The opamp has two input terminals, the positive terminal (+) called the non-inverting input terminal and the negative terminal (-) which is called the inverting terminal.

When the input signal is connected to the non-inverting terminal, the amplifiers' magnification, called the gain, is in the positive real number range while a connection to the inverting terminal produces a gain with a negative value. The signal multiplying property of the opamp which is the gain of the amplifier could maintain a value as high as 1, 000, 000 making it a perfect choice for both input and output transducers.

^{[the characteristic impedance Z0 signifies the free movement of signal in one direction in absence of reflection. Credit: wikimedia. CC3.0 license. Author: Omegatron]}

Another vital part of signal conditioning is the impedance matching. Generally, impedance is the total resistance offered by an electric circuit to an applied voltage. Impedance matching is very vital when transferring signal between circuits (in this case from the sensor to the control circuits and from the control circuit to the transducers). When the total resistance of two interacting circuits are matched, there is a maximum signal transfer between the two circuits as signal reflection is kept at the minimum.

Being able to isolate the input signal from the output signal is also part of conditioning the sensors and transducers for the job they will perform. The signals picked up from the environment may also contain some noise components, hence, signal filtering is also a vital part of signal conditioning for the IoT system. Signal filtering can be done by frequency selection using analog filters like the band pass filters, low pass filters, high pass filters and or all pass filters.

Once a viable signal has been picked from the environment, conditioned and safely transported to or from the controller system, the next phase is to determine what part of the IoT system is controlled by the control system.

The Actuators

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Wikipedia the free encyclopedia defined an actuator as and I paraphrase;

Any system component which has the responsibility of moving or controlling the mechanism of such system.

The actuator component of the IoT takes "directives" directly from the controller system usually in the form of electrical signal and converts this signal into a mechanical movement or motion. The sources of energy for the actuator could be from a pneumatic system (you can read up on an awesome post by @adetola on pneumatic systems here), hydraulic system, electric current, etc.

A very good example of a widely used actuator for IoT system is the relay. A relay is typically an electromagnetic switching system which requires a little amount of electric energy for operation and can open or close circuits that has lager electrical current.

The main component of an electrical relay system is the electromagnet which consists of a soft iron and an armature winding. When a little current flows through the armature winding, the soft iron becomes a temporal magnet which pulls a metal piece suspended just above it by a spring. By pulling the suspended metal piece towards the magnetized soft iron, the relay can close or open electrical circuits to which it is attached to.

Usually, relays configured to complete circuits are called normally open (NO). This is because when current is supplied to the electromagnetic circuit of the relay, the metal suspension pulled towards the soft iron which as already stated, completes a required circuit. This type of relay are very common. Another type of relay is the normally closed (NC) relays. They are normally used to break out of a circuit. When current flows into the electromagnetic circuit of the relay, metal suspension which is made to make contact with the soft iron is pulled away from the temporal magnet and by so doing, it breaks out of any possible electrical circuit.

Another widely used actuators in the IoT technology is the transistor. The transistor can function both as an amplifier and also as a switch. The transistor is a better switch than the relay in terms of speed and accuracy. The transistor is a semiconductor electronic component which changes its conductivity in accordance with an applied voltage or current. Basically, it is a three terminal device with terminals Base, Emitter and collector corresponding to the amount of electron concentration around each terminal. When the transistor is used as a switch, passing voltage through the base in a process called biasing, can complete a connection between the emitter and the collector.

Hence, the transducers and sensors educates the controller system while the actuators forms the execution system for the controller system of the IoT.

The Communication System

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Automation is an IoT system void of remote communication. With a proper communication system, the transducer and sensors, the actuators and the controller system is made to perform certain functions remotely. We're able to remotely check or alter the temperature of our homes using the IoT system because of a functional communication. Popular communication system used in the IoT technology includes;

Li-Fi

Wi-Fi

Internet connection

Bluetooth, etc.

The Bluetooth offers a type of connection called a Personal Area Network (PAN). A PAN is an inter-connectivity between devices that are within an individual's environment usually within the range of 10 meters though improvements on the Bluetooth technology has extended this range far beyond the stated distance.

Most IoT systems can communicate with a local system using all the above mentioned communication system with choice of connection type being either distance or cost. When the controller system is meant to span a very short distance between just a user and the IoT system, the Bluetooth connection is used.

Both the Light Fidelity and the Wireless Fidelity creates a type of connection called the Local Area Network. Li-Fi is an improved version of the Wi-Fi technology which instead of making use of the radio waves as the Wi-Fi, makes use of light. A local area network is a type of connection between computers that are within a building or group of close buildings which are not more than 1 kilometers apart. This was an initial idea of local area network but this distance can be made to span across millions of miles using an internet technology called tunnels which makes connections that are miles apart appear to be within the same locality.

Hence, when the controller system is desired to span across more than an individual or group of individuals over a longer distance, the Wi-Fi or better still the Li-Fi connectivity is used.

Internet connectivity provides access to an IoT system at any location in the world. The internet is regarded as the network of networks and it comprises of several interconnection of local area networks. Internet connectivity might seem like the best option for you IoT system but financial involvement might make the option seem not so good after all. An IoT which is controllable over the internet would require a connection with a local internet service provider and a valid external IP address.

Not all IP addresses are usable on the internet. The IP address is broadly divided into two; the public and private IP address. The private IP addresses are only usable within an organization or within a network under a specified administration. A connection to the ISP is usually accompanied with an IP addressing scheme which withing the public domain. Hence, when choosing an internet connection for your IoT system, do consider contacting a local ISP.

The Controller system

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Every other components of the IoT system is connected directly or indirectly to the controller system. It is the intelligent part of the system. The controller system consist broadly of a Microcontroller and an Application. Automated systems which is usually a subset of IoT maintains a controller system consisting of just the microcontroller or microprocessor.

Microcontrollers are specialized processors which can process voltage signals from the sensors and with such information either intelligently (in the case of automation) activate the necessary actuators which in turn triggers some mechanism or remotely inform a user (in the case of IoT) of the action it has already taken or wait for a command from the user(s). Calibration of sensors are also done in the microcontroller and this involves selecting a desired voltage or current value of sensors at which some desired action is carried out by the microcontroller.

^{[credit: flickr. Creative commons license. Author: Conifer]}

For example the LDR (light dependent resistor) can be calibrated selecting a particular voltage value of the resistor at which the controller can perform a particular function like switching on both the camera and electric bulb or series of functions.

The use of applications like the web application and or mobile application to remotely carry out a function is not uncommon in the field of IoT. These applications provides a very user friendly interface often requiring no expert knowledge of the IoT to operate the system.

Summary

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The basic component making up the internet of things are the signal transducers and sensors which can interact directly with the human environment and help educate the controller system which is the brain of the IoT. The communication system of the IoT can range from setting up a personal area network powered by Bluetooth to world wide communication via the internet. The various components of the IoT are controlled using a microprocessor or microcontroller.

REFERENCES

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1. Internet of things -wikipedia
2. Transducers and sensors -electronics-tutorials
3. actuator -wikipedia
4. How relay works -explainthatstuff
5. Light Fidelity -wikipedia
6. The operational amplifier -allaboutcircuits

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