Today, many devices such as smart phones, smart TVs, smart watches are connected to the internet. With the development of mobile networks and the internet, the number and variety of these smart devices are increasing day by day. This increase has made it inevitable for computers connected to each other to exchange data with devices and objects connected to each other. Connecting everything imaginable, from cars to clothes, from digital clocks to electricity and water meters, from coffee machines to soccer balls, from smart homes to smart cities, has turned into the Internet of Things (Figure 1.1).
The Internet of Things ( IoT ) is a network where millions of smart devices and sensors connected to the Internet communicate with certain protocols. The concept of the Internet of Things ( IoT ) was first introduced in 1999 by Kevin Ashton in a presentation on RFID technologies. In the Internet of Things, there may also be situations where smart devices are not connected to the Internet. Examples of this situation are RFID, RTLS and Beacon etc. technologies can be given to produce information with some devices.
In this period when everything has become smart, there is no area where the Internet of Things has not entered (Figure 1.3). The areas where the Internet of Things is most used are:
• Smart home building automation
• smart city
• energy systems
• Agriculture and greenhouse cultivation
• disaster management
• military and security
• Wearable technologies
• Government Policy
The Internet was born as a connectivity solution that connects local networks so they can exchange information. It is a form of communication between people. The possibility of linking objects opens up a new paradigm in communication, because objects need to generate the information they exchange and basically act based on certain parameters.
Watering our garden has hitherto been a manual job. Even if we install sprinklers, it is up to us to turn them on every time we need to water them, thinking that the soil has enough moisture. We can program a timer to start and stop watering without manual intervention, but it will start and stop even if it rains.
An IoT -based irrigation solution has at least the following features:
The points mentioned constitute a highly efficient solution: the sprinkler will deliver water to the ground only when the sensor data meets the predetermined conditions of the processing unit (basically soil moisture parameters are below acceptable and no rain is falling). But that's not all. The IoT solution is an important source of information. From the data provided by the sensors, irrigation, precipitation cycles, changes in soil moisture, etc. It is possible to have statistics about
There are many products that use the Internet of Things. These products are used in various industrial areas, homes, hospitals, vehicles, greenhouses, etc. used in places.
Different vertical markets determine the type and implementation of an IoT solution. For example, a solution for the oil industry will require a communications infrastructure such as satellite communications that provides wide geographic coverage. In contrast, a home security system can operate with a local communications infrastructure (a private network), which requires greater security and reliability.
|Satellite||Cellular||LPWA||Dedicated local network||Shared local network|
|Extensive coverage||Extensive coverage||Extensive coverage||Local coverage||Local coverage|
The communication infrastructure of the Internet of Things can be as follows:
When we talk about IoT solutions, energy plays a fundamental role. Different markets require different solutions, and each solution has its own power requirement.
The oil industry implements IoT solutions in areas far from city centers. It is very important to consider that devices have guaranteed power for a long time (usually long-lasting batteries).
On the contrary, the energy in the assembly line of the automotive industry will be absolutely guaranteed and there will be no problem for the IoT solution.
Data management and migration
At this point, it is clear that telecommunications infrastructure is key to exchanging data for an Internet of Things solution. The predicted exponential growth in the number of connected devices in the coming years will generate a database tsunami of data through communication systems.
Bits and Bytes
The unit of measurement in a binary-based data system (such as those used to encode information in computer systems) is a bit (binary. digit) . A bit can only have two values: 0 and 1. A byte is the minimum unit of information, which is an 8-bit string.
The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) have defined a standard for prefixing binary-based data volumes. However, the prefixes of the International System are the most used to represent volumes of data:
|Prefix||Prefix + “byte”||Symbol||Factor and value|
|byte||B||100 = 1|
|kilo||kilobyte||kB||103 = 1.000|
|mega||megabyte||MB||106 = 1.000.000|
|giga||gigabyte||GB||109 = 1.000.000.000|
|tera||terabyte||TB||1012 = 1.000.000.000.000|
|peta||petabyte||PB||1015 = 1.000.000.000.000.000|
|exa||exabyte||EB||1018 = 1.000.000.000.000.000.000|
|zetta||zettabyte||ZB||1021 = 1.000.000.000.000.000.000.000|
|yotta||yottabyte||YB||1024 = 1.000.000.000.000.000.000.000.000|
Let's turn this data into reality. If we measure what is happening on the Internet for one minute, what will we find?:
In just one minute, more than 2,000 terabytes of information circulate on the Internet.
The advantages of the Internet of Things are:
The disadvantages of the Internet of Things are:
Basic circuit elements are used to connect to the Internet and to control many objects in the environment over the Internet.
The resistance to electric current is called resistance. The resistor symbol is the letter "R". The unit of resistance is Ω (Ohm). The values of the resistors are read by using the resistor color codes in Figure 1.4.
When the resistors are examined, it is seen that the tolerance is positioned separately at the end. In this way, reverse reading situation does not occur in the resistors. When the resistance values are calculated, the following results are obtained:
LEDs are diodes that emit light when current flows through them. They also act as zener diodes by dropping a constant voltage across them . LEDs have different voltage drops according to their colours, but usually 2 V is assumed, and calculations are based on 2 V 20 mA (milliAmps).
Voltage drops according to LED colors are given in Figure 1.5. In LEDs, the long leg is the Anode and the short leg is the Cathode .
|LED Colors||Required Voltage to LED||Current Required to LED|
|Red||1.5-2.5V||10 - 20 mA|
|Green||2.2-3.3V||10 - 20 mA|
|Blue||3.3-4.5V||15 - 30 mA|
|Yellow||1.8-2.8V||10 - 20 mA|
|Wite-Ultraviolet||3.3-4.5V||15 - 30 mA|
Figure 1.5: Voltage and current values needed according to LED colors
The values here are average values. Values should be calculated from the documentation of the purchased LED. Source Voltage = Resistor Voltage + LED Voltage formula is used to calculate the resistor to be installed before the LED.
There are two types of buzzer , active (circuited) and passive (circuited ) .
Active buzzer can be operated with any pin, while passive buzzer can be operated using PWM method.
The transistor is the switching element that provides the control of high electrical loads with small electrical signals. The transistor usually consists of three legs. These legs; It is called base ( bayz - B ), emitter ( emitter - E ) and collector (collector - C ). There are two types of transistors, NPN and PNP.
NPN: With the small voltage applied to the bayz leg, it allows high voltages to flow between the collector and the emitter . When the voltage applied to the Bayz leg is interrupted , the connection between the collector and the emitter is interrupted.
PNP: When no signal is applied on the base leg , it allows high voltage to flow between the emitter and the collector, while when a low voltage is applied on the base leg, the connection between the emitter and the collector is cut.
The relay is a structure that contains a coil for magnetization and COM, a normally closed switch and a normally open switch (Figure 1.6). When no current is applied to the coil pins, the NC (Normal Close-Normally Closed) pin is in contact with the COM (common) end. The NO (Normal Open-Normally Open) pin is separate from the COM lead. As a result of the voltage applied to the coil legs of the relay, the current passing through the coil magnetizes the coil and pulls the COM terminal towards itself. After this process, the COM pin leaves the NC and contacts the NO pin. Due to this structure, small voltages and very large voltages can be controlled by isolating microcontroller systems from high voltage systems. All electrical equipment in homes can be controlled with relays. High voltage connections in houses are made using COM, NC and NO pins.
The button is a circuit element that provides a connection between the two pins 1 and 2 when the (A) button on it is pressed, and cuts the connection between the two pins when the (A) button is pressed, and returns to its original position (Figure 1.7).
There are two-pin and four-pin versions of the button. In four-pin buttons, two pins that are close to each other show the feature of a button, while two pins that are far from each other are interconnected (Short Circuit). In this way, the button feature is seen between pins 1 and pin 2.
There are two types of switches, limit switches and on-off switches.
Breadboard is an element needed to easily assemble the components to be used in the circuit. Thanks to the breadboard , there is no need to solder the circuit elements. This provides the opportunity to reuse the elements and easily change the circuit design wherever desired. Breadboards are available in different sizes in the market. It is important to choose the most suitable breadboard according to the circuit design .
The point to be considered when using breadboard is the vertical and horizontal stripes.
When the breadboard in Figure 1.9 is examined, the area shown in red is called the bus strip. The bus strip is generally used for power supplies. The bus strip is transmitting vertically. The “+” and “-” labels found here are not binding, but they are labeled as “+” and “-“, as the most needed connections in the circuits made. The area shown in orange is called the socket strip and is used to plug in components in the circuit. The middle part, shown in blue, is called the integrated region, and it cuts the breadboard in half, breaking the conduction between the left and right parts of the breadboard. In other words, socket strips consist of five horizontal pins.
When placing the elements on the breadboard, attention should be paid to the bus strip and socket strip. Example layouts should be as in Figure 1.10. Bus strip and socket strip connections were not taken into consideration in incorrect placements. Since the current to be applied will choose the easiest way, the resistor connections will have no effect or effect on the circuit. In another faulty connection, cross connections are not preferred because they make it difficult to read the circuit.