“Any physical devices embedded with sensors and integrated with computation machine having internet connection for communication and interfacing”
Now days, internet of things is dominating the whole industry. Iot has become pervasive in every field of life. Every industry such as manufacturing, transportation, vehicle, security, electronics etc. is seen impressed by iot technologies. Even the healthcare department is gathering much from this amazing technology. Many industries are spending much for the advancement in iot devices. Even, universities are conducting researches for advancement in this field. As internet of things is prevising every field of life therefore, everyone is keen to learn about this amazing technology. In this article, you will find a complete detail of general working of any iot application and iot devices involved in these steps. We will also represent some iot icon sfor better visualization of concepts. Here is a stat of increasing iot devices every year according to statista
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Iot infographics representing iot devices
General Working of iot device:
Iot device is any physical device with sensors embedded in it and internet connection to communicate with user. We can explain this with a simple example of refrigerator. A number of years ago, you have manual devices in your homes. However, today, most of you have intelligent iot based devices (such as refrigerators) in our home, which can automatically sense threats in machinery, can sense components in refrigerators and many other useful features. This is all due to the advancement in iot technology. Internet of technology has four parts
- Computing Machine (Microcontroller or processor)
- Actuators (Motor or automatic switch )
- Internet connection for communication
Let us find all these parts in above example. First, we find the role of sensors. Iot based refrigerators can have many types of sensors embed on it. For example, it can have sensors, which senses the voltage supplied to the refrigerator. It can have sensor which can measure quantity of components in refrigerators (it can either done by checking weight or it can be visual) or it can have sensor which monitors behavior of compressor. Therefore, there can be many other types of sensor embedded on it depends on need and features.
The second part is a computing machine. Just as the computer takes data, performs calculation on it and returns some result. Similarly, these iot systems have some computing machine for calculation on data obtained from sensors. Generally, microcontrollers used for this purpose. Microcontrollers are same as processors in computer but these are special purposed designed for some specific tasks. Therefore, these microcontrollers perform calculation on data and run the machinery depending on data.
Then next come the main part due to which this technology called internet of things and this called internet. Now, if the calculation on data shows some error or threat, these devices have internet connection to warn the user or other action. For example, the sensor monitoring the machine detects damage, the machine will communicate with user via internet or machine can contact mechanic if the condition is bad. Alternatively, if the sensors sense some fire or heat in system, the system will immediately communicate with the fire brigade station in this regard.
Then, come the last part of these devices, which performs action depending on data called actuators. These actuators can be anything such as switch, motor or any light. For example, if sensors in fridge detects fire, they will immediately open the connection between refrigerator and main connection using some switch, which is actuator. You have often observed in childhood that when we open the door of refrigerator, refrigerator lights on and off when we close the door. These are also actuators.
From the above example, you have gain a general understanding of each part in internet of things technology. Now we will look at each part in detail
- SENSORS : Sensors are the devices which is used to sense the behavior of environment. These used to monitor the condition of the surrounding and collect data of specific type. There are many types of sensors are available in the market. For example, thermistor is a sensor, which used to sense the temperature of the surrounding. Similarly, many sensors are available which can measure humidity, light, water level and much more. These sensors detects data in two ways
- Resistive sensor: microcontroller can only access data in the form of voltage signal. However, not all the sensors outputs data in the form of voltage. Therefore, we have to apply some circuitry to convert the signal into voltage signal. The resistive sensors change the value of resistance with changing Resistance. Therefore, we apply circuit-containing resistance in series with resistive sensor. Therefore, that voltage will be different for each change in resistance of sensor. Therefore, we can use these different values of voltage for sending signal to microcontroller. For example, photo sensors used for detection of light have different resistance at different light. Therefore, we connect it in series with other resistors as shown in icon below and difference in voltage can used to manipulate microcontroller. Some other resistive resistor examples are thermistors, ultrasonic sensor, water level sensors etc.
- Voltage sensors : As microcontroller accepts only analogue voltage signal, therefore, for ease sensors are developed which outputs the change in difference with voltage difference across them. So, these sensors can be used without any external circuitry. These type of sensors have data manipulation in controllers very easy. Some examples of these voltage sensors are LDR sensors, water detection sensors etc.
These sensors can categorized further into another category: Analogue and digital sensors
These type of sensors also called binary sensors due to their binary nature and 0-1 behavior. These sensors are like switch, which can be either on or off. For example, light detection sensor. These sensors will immediately off when they detect light otherwise off. These sensors can have only two states: On or off and nothing between these two states.
Unlike digital sensors, analogue sensors can detect different level between on and off state. For example, if you want to analyze the level of light in surrounding, we have to use analogue sensor. Digital sensors cannot be used for this case because there can be different level of light such full bright, less bright, dim, and full dark etc. Therefore, we can use analogue resistive sensors in this case which changes the value of resistor across depending on different light levels.
Microcontrollers: Computing Machine:
Every iot device has computing machine for computing data from sensors called microcontrollers. It is a compact integrated electronic chip designed for computing specific task. Some examples of microcontrollers are Arduino, raspberry pi and tiva development boards. A typical microcontroller has
- I/o Pins (input/output)
You have often heard that microprocessor is a brain of computer. This is because microprocessor is used compute all tasks in a computer. Similarly, iot microcontroller has a processor for manipulating data obtained from sensors. The difference between computer processor and microcontroller processor is that computer processor is general computing machine while microcontroller processor is used for one specific purpose.
every microcontroller has memory embed on it which is used for storing the code and MPU (memory protection unit which is used when processor is involved in interrupts). The memory can be program memory and data memory.
Every microcontroller has some input/output pins to interface with the sensors and actuators. These pins can be analogue and digital.
Peripheral are i/o devices which are used to send data to processor in binary format via input and output ports interface.
microcontrollers can additionally have ADC, DAC, Ethernet and Wi-Fi communication protocols and many other things.
The main thing due to which this technology named “Internet of things” is Internet connection. So, connecting to internet connection is considered to be the essential part of the internet. Every iot device must have internet connection to interact with user via user interface on mobile or web applications. So, every microcontroller follow some networking protocols to interact via Bluetooth, WI-FI, Ethernet, RFID, Cellular satellite or LPWAN etc. The efficient network connection must consider low power, large range and ability to transmit huge amount of data.
Actuators are like transducers (Any device that converts one form of signal/energy to another form) which converts electrical signals from microcontrollers to perform different physical tasks such as derive a motor, turn on light or something else.