106105166.pdf

Introduction to Internet of Things Prof. Sudip Misra Computer Science andEngineering IIT Kharagpur  INDEX S.NO TOPICS PAGE.NO Week 1 1 Introduction to IoT- Part-I...

Introduction to Internet of Things Prof. Sudip Misra Computer Science andEngineering IIT Kharagpur  INDEX S.NO TOPICS PAGE.NO Week 1 1 Introduction to IoT- Part-I 4 2 Introduction to IoT- Part-II 27 3 Sensing 41 4 Actuation 60 5 Basics of IoT Networking- Part- I 75 Week 2 6 Basics of IoT Networking-Part II 93 7 Basics of IoT Networking-Part- III 105 8 Basics of IoT Networking- Part-IV 120 9 Connectivity Technologies- Part-I 128 10 Connectivity Technologies- Part-II 147 Week 3 11 Connectivity Technologies- Part-III 164 12 Connectivity Technologies- Part- IV 181 13 Connectivity Technologies- Part- V 199 14 Sensor Networks- Part- I 214 15 Sensor Networks- Part- II 233 Week 4 16 Sensor Networks- Part-III 251 17 Sensor Networks- Part- IV 273 18 Sensor Networks- Part- V 292 19 UAV Networks 305 20 Machine to Machine Communication 321 Week 5 1 21 Interoperability in Internet of Things 336 22 Introduction to Arduino- I 356 23 Introduction to Arduino- II 374 24 Integration of Sensors and Actuators with Arduino- I 392 25 Integration of Sensors and Actuators with Arduino- II 405 Week 6 26 Introduction to Python Programming- I 416 27 Introduction to Python Programming- II 432 28 Introduction to Raspberry Pi- I 456 29 Introduction to Raspberry Pi- II 477 30 Implementation of IoT with Raspberry Pi- I 491 Week 7 31 Implementation of IoT with Raspberry Pi- II 507 32 Implementation of IoT with Raspberry Pi- III 525 33 Software Defined Networking- Part- I 542 34 Software Defined Networking- Part- II 563 35 Software Defined IoT Networking- Part- I 575 Week 8 36 Software Defined IoT Networking- II 588 37 Cloud Computing-Fundamental 605 38 Cloud Computing-Service Model 628 39 Cloud Computing-Service Management and Security 645 40 Cloud Computing- Case Studies 665 Week 9 41 Cloud Computing- Practical 687 42 Sensor-Cloud- I 713 43 Sensor-Cloud- II 727 44 Fog Computing- I 748 45 Fog Computing- II 765 2  Week 10 46 Smart Cities and Smart Homes- I 784 47 Smart Cities and Smart Homes- II 805 48 Smart Cities and Smart Homes- III 822 49 Connected Vehicles- I 839 50 Connected Vehicles- II 857 Week 11 51 Smart Grid- I 874 52 Smart Grid- II 896 53 Industrial Internet of Things- I 919 54 Industrial Internet of Things- II 935 55 Data Handling and Analytics- I 957 Week 12 56 Data Handling and Analytics- II 977 57 Case Study Agriculture 995 58 Case Study Healthcare 1011 59 Case Study Activity Monitoring - I 1030 60 Case Study Activity Monitoring - II 1040 3  Introduction to Internet of Things Prof. Sudip Misra Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture - 01 Introduction to IoT-Part – 1 So, the first lecture is going to be on the Basics of Internet of Things. So, in this lecture we are going to get introduced to the different fundamental concepts behind IoT and the basic technologies connectivity devices that are required and an overall understanding about how IoT’s are made. So, we are going to have in this lecture an understanding about all of these concepts, but first let us get motivated about why IoT is required. So, it has been anticipated that very soon all the different things that are going that we are seeing around us and that we have around us are all going to be internet worked. They are all going to be interconnected. So, at present what we enjoy as services, as internet based services is basically a connection of different computers and computing devices. So, basically this capital I internet that all of us use is basically a global network or an internet work of different computers and computing devices. Now, what internet of things says is that the scope of this internet is going to be expanded. So, it is going to be expanded beyond computing and computer devices being connected. It is going to interconnect different things that physical objects that we see around us, the different objects such as the lighting system in a room, the lights, the fans, the air conditioners and anything and everything including things such as the toothbrush, the microwave oven, the refrigerator and so on so forth and not only in our homes, but also in our businesses such as internet working different machines, internet working different equipments and so on. So, each and everything that we see around us that we use at our home in businesses, in workplaces, everything being internet worked. So, this is the whole vision of internet work of things, internet of things. Now, there are several challenges that are going to arise if we want to do it, but before that let us also discuss about why it is going to be required, why internet of things has become so popular, why it is going to be required? The reason is that IoT is envisaged to be able to provide advanced level of service to the society to the business and so on. So, advanced levels of services can be offered with the help of IoT based technology. 4 So, what is going to happen is, these different things, the chairs, the tables, these lighting system, you know the watch or anything and everything that you can think of, all of these are going to be fitted with embedded systems, embedded electronics and information technology, so that they have some basic computing platform in them, attached to them and then, they are going to be acting as different nodes of that particular internet, the IoT internet of things, right. So, what is going to happen is these systems, these things are going to be all equipped with embedded systems and these embedded systems along with embedded electronics, embedded processor, embedded communication systems and so on. So, they are going to help in connecting different other things that are around them and depending on the application requirements, depending on the specific goals of the business and then, a big internet is going to be formed which is much bigger than the current internet of computers and that is the internet work internet of things IoT. Now, IoT is one of the building blocks that is considered to be of use for developing smart homes and smart cities. So, at present not only in our country, but throughout the world there is a lot of interest on developing smart cities and smart homes. So, IoT is one of the enabling technologies to make the city smart, to mix make the home smart. So, how it is going to be done, that is going to be more evident as we proceed through the different lectures and the different intricacies that are going to be there in building this complex internet of things is going to be evident through different lectures that we are going to go through in this particular course. 5 (Refer Slide Time: 05:48) So, going forward Internet Technology that we have as I have already said it is going to expand beyond the connection of simple computers. So, we are going to connect or internet work different machines, different tools typically, but not necessarily using wireless technologies, such as Wi-Fi cellular technologies, Bluetooth Zigbee and different other wireless technologies that are available to us. Now, in order to be able to do it, what is going to happen is because the number of things is very large, much larger than the number of computers that are available, so it is going to increase the number of nodes in this particular network. So, IoT in other words is going to have large number of nodes, the IoT internetwork is going to have large number of nodes and each node corresponding to the different distinct objects or different things that exist in the physical world. So, the things basically are going to explode the number of connected things, are going to explode in time with time. So, the things that are connected to the internet are going to be projected to cross the 20 billion figure in the near future. This is what has been predicted. So, a large number of things, billions and in fact, billions and trillions of things are going to be connected to the internetwork of things. So, at this point I should also mention one more thing that this internetwork of things can be construed to be built in two different ways. One way is to expand the scope of the current internet. That means, the internet of computers this is one way, so you expand. 6 So, essentially what is going to happened using this particular approach is all these different things are going to be connected to the existing internet. So, this internet is going to be expanded further. It is going to become much bigger than what it is at present with only the computers connected. This is the first approach. The other approach is to build a separate internetwork of these physical objects from scratch. So, one is basically expanding the existing internet and the other one is a separate internetwork which is going to be built from scratch. So, irrespective of which one we adopt, each of these approaches has its own separate challenges that have to overcome. So, going back we have the unification of different technologies that becomes very much mandatory we have. So, internetwork of things is not a single technology. Physical devices can be of different types of physical devices having different configurations, different specifications and so on. Each of these supported through different other systems such as cloud technology, big data machine, learning networking computer vision, you name it and all these different technologies from electrical sciences and some from even mechanical sciences are required in order to build IoT. (Refer Slide Time: 09:40) So, talking about the origin of IoT. So, in the 2000, what we are going to witness is a new era of ubiquity. So, in this era of ubiquity, what is going to happen is not only that we are going to have anywhere, any place, that means any place any time connectivity or services relating to connectivity. That means, internet or network connectivity of 7 different types, but also the service of connecting anything. So, anytime anyplace anything, connectivity is what is going to be observed in this new era of ubiquity. So, that is going to result in billions and trillions of things. Humans, everybody being connected and consequently what is going to happen is the number of humans that are on the earth that is going to this number, this figure is going to be outnumbered very soon with the number of things that are connected to the internetwork of things internet of things and consequently what is going to happen is, all these different devices, all these different things, they are going to send lot of data. This data has to be handled properly, this data have to be analyzed and this is what we are going to cover in one of the next lectures. So, what is going to happen is this internetwork, the new internetwork that we are talking about, the internet of things is going to be very complex network with much wider scope than the current internet and with many more complexities and this is currently the vision of internet of things and all these lectures that we are going to go through in this particular course. All the other lectures that we are going to go through, they are going to cover the different challenges and how there are different tools that are available in order to, what are the different tools that are available in order to address these different challenges. So, we are going to go and we are going to get introduced to all these different challenges and the different tools that are available in this particular course. We are going to mostly understand the different concepts that are behind them and typically because it is an introductory course, we are not going to go through each of these different technologies that are available to us in too much of detail, but at a level that will help us to understand the basic concepts for that are required for designing internet of things. So, there are different enabling technologies for internet of things. 8 (Refer Slide Time: 12:39) RFID is one we know at present in the market places and different places in the society you know and wherever we go, we see that RFID technology being used RFID tags, RFID readers are being used. So, RFID based devices are required for building internet of things. Sensors is another one which is according to me one of the most important enabling device or enabling technology for building internet of things. Sensors and actuators are what we are going to cover in one of the next lectures very shortly and the other things are different networking devices, different connectivities, different communication paradigms and so on. So, these are also required in order to connect these different sensors, RFIDs and different other physical devices that have to be internetwork to form the IoT. Finally, I would like to mention that at present there is lot of interest in the nanotechnology domain. So, people are talking about building internet of nano things, internet of nano sensors and so on. So, you know what is going to happen is there are going to be very small sized nano size nano in the order of nano sized devices that are going to be used for different purposes. For example, there could be these nano capsules which can be consumed and finally, which are going to be excreted after you know after they have performed their functions. So, these nano devices are going to be used, they are going to be swallowed and consumed and then you know once that is done in the form of capsules, they are going to 9 be internetwork. These different nano devices, these nano capsules are going to talk to each other. So, these nano devices, nano communication devices are being conceptualized. At present people are thinking about building these nano devices that can be used to form the internet of nano things. So, once we have this internet of nano things, the horizon of internet of things is going to be expanded much further. (Refer Slide Time: 15:22) So, we already have seen that when we are talking about IoT, it is mostly about networking of physical objects and these physical objects are embedded with you know the different embedded electronics that communicate and sense and interact with the internal states or with the external environment in which they are operating. So, either they are interacting with each other, they change their different states or they are interacting with the inter external environment in which they are operating. 10 (Refer Slide Time: 15:57) There are different characteristics, there are different characteristics of IoT. So, first of all this IoT that we develop that has to be efficient. It has to serve efficiently the requirements of the applications for which they are deployed. They have to be scalable because we have already seen that in IoT systems, we are talking about large number of things, we are talking about not simply millions of things, but in several billions and trillions, we are talking about the scalability is very important, consideration is very important issue that has to be addressed. So, even if the number of sensors and the sensing devices IoT devices are going to increase, the overall network performance should not be compromised. So, you know this is challenge in terms of the network. So, from a networking perspective, it is a challenge that has to be worked on. There has to be unambiguous meaning and addressing architecture. So, this is very important. So, all these different devices already we have witnessed that addressing in the IPV4 context in the regular existing internet context is a big issue. So, we are talking about naming and addressing different mechanisms of naming and addressing with the help of IP technology, DNS etcetera etcetera. We already have seen that these can be used in order to you know address these problems of addressing and naming in the context of the present internet and now, when we are expending this 11 internet in this large scale. So, what is going to happen is, we are going to run into a bigger problem with naming and addressing. So, we need a new mechanism for naming and addressing of the different nodes, these physical nodes, the physical objects that are fitted with embedded systems. So, another thing is that in terms of the resource requirements, each of these nodes are typically very low power. They have very low resources and they have to be you know whenever they are not required, they have to be put to the sleeping mode, they have to go through a sleep cycle. So, that means whenever they are not being used, they are not being active. They have to be put in a sleep state and whenever it is required, they have to be made active. These devices can be mobile, they can move. For example, a smartwatch you know whoever is wearing the smartwatch, when they move, this node also moves, the smartwatch also moves. So, mobility like this becomes a very important problem in the context of IoT networks. Mobility of the devices and the mobility of the sub networks also is possible. So, part of the network becomes mobile and in extreme cases even larger network can also become mobile. So, IP based addressing may not be always very suitable in this sort of scenario. So, what are the different alternatives? There are different people, different researchers globally who are working on how IoT technology, how naming can be a different form of, naming can be designed in order to support this IoT technology and intermittent connectivity is another characteristic that is typical of IoT. These devices, they move, they get the network and the subnetworks get partitioned. One device which is in connectivity with another device at a later instant of time may not be connected. So, this is another problem that has to be taken care of. So, for example there is this opportunistic mobile networks which is a topic which can help in addressing this particular problem, this technology. The Waymond technology can help in addressing this particular problem. So, opportunistic mobile networks are useful in order to address the problems of intermittent connectivity between the different nodes in the network. 12 (Refer Slide Time: 20:30) In terms of application domains, there are you know IoT is attractive in different applications, spheres application, domains spheres. For instance, manufacturing and business, healthcare, retail, security and so on. So, among all of these, it is estimated that most of the market share with IoT goes with the manufacturing at an business sector, so 40.2 percent approximately. Next is the healthcare and third is the retail sector and fourth is the security, surveillance, safety surveillance and so on with the help of IoT based systems. (Refer Slide Time: 21:21) 13 So, when we talk about business and manufacturing, we are talking about how to improve the overall supply chain, what are the different equipments that have to be introduced and different sensors and actuators can be fitted to them, the different robotic machinery can be used in order to improve the business processes. Second is the healthcare. We are talking about portable healthcare monitoring telemedicine in a much more bigger way. That means, much remote areas can also be connected the different healthcare facilities, hospitals, nursing homes, doctors, nurses. Irrespective of where they are, they can still monitor the healthcare condition, the health condition of the patients that they are treating. So, portable health monitoring electronic recordkeeping is another. So, automatically because you know in medical domain record keeping is a very important concern. So, electronic record keeping automatically things are the records, medical records are going to be archived. They are going to be stored, they are going to be you know maybe they can be even further analyzed to grow some meaningful conclusions from them and so on and different pharmaceutical set safeguards can had in using the IoT technology. In the case of retail sector as well tasks, such as inventory tracking, smartphone purchasing, anonymous analytics of consumer choices, these are the different things that can be done efficiently through the use of IoT technology. Security is another biometric and facial recognition looks, then the remote sensors and so on. You know fingerprinting based or face recognition based or different eye rays recognition based you know, so these technologies can be connected and used with the help of IoT and you know this sort of security mechanisms can be developed. 14 (Refer Slide Time: 23:36) Now, when we talk about this interconnectivity of different devices, we see that this interconnection or connectivity between the different devices has evolved over the years. First it started with these individual cash machines or the ATMs being internetworked. The web became very popular. So, you know everybody connects to the internet or the web in order to get access to different information, send emails and so on and so forth. Many different things are performed by different web users. At present smart picker meters then became popular. So, smart meters are used at different homes in a city. These smart meters, they can be programmable and they can record different things. Even you can program the smart meters at your homes in order to do different things like load balancing, electrical load balancing, efficient use of electricity you know using electricity during non-peak hours, pricing, accordingly in the pricing mechanic choosing different options for service of electricity that is provided by the service provider and so on and then, we have digital locks. Biometric based digital locks are very popular. We have smart healthcare, smart vehicles, smart cities and smart dusts. So, these are the different technologies that have evolved, these are different connected you know device based technologies that have evolved over the years. 15 (Refer Slide Time: 25:17) So, ATM and web are relatively old by now. One comes from 1970s and the other one from 1990s, but smart meters became very popular in the 2000s. Digital locks are very popular at present. So, smartphones can be used as locks to lock and unlock the doors remotely at your homes or at your businesses and these locked keys and so on. They can be easily changed and one can be granted access to a particular facility. One means in a business, the employees or the different guests, they can be granted access to different facilities through the digital locks much more easily than the conventional locks. 16 (Refer Slide Time: 26:10) Smart healthcare connected vehicle, smart vehicles you know these are quite common smart cities as I was telling you is very popular at present not only in India, but throughout the globe. So, in smart city, people are talking about deploying smart different infrastructure. These infrastructure which can communicate with each other, they can be used by different owners and the different operations in a city and different functions of the different offices, etcetera you know. So, all these things, offices and different other public places, all these things can be monitored and the operations can be improved much more easily and also, the information dissemination because you know all these different devices, they are typically fitted with sensors. So, these sensors are going to throw in lot of data. So, dissemination of this particular data is very important, handling of this particular data is very important. In the context of smart cities, smart dust is another thing where the computers that are smaller than a grain of sand can be spread or injected almost anywhere to measure chemicals in the soil or to diagnose problems in the human body. 17 (Refer Slide Time: 27:27) So, in the modern day IoT people are talking about different applications such as smart parking, structural health monitoring noise urban maps; that means, noise maps in a particular city or an urban environment smartphone detection traffic condition, smart lighting systems, waste management, smart roads river flood monitoring, smart grid tank monitoring, water tanks etcetera, tank level monitoring, photovoltaic installations, water flow monitoring, stock calculations, access control presence of different liquids hazardous materials and so on and so forth. Large number of applications are envisaged. In fact, you know there are many IoT oriented systems have been built already. They have been prototyped. Some have been much more advanced than in that than a simple prototype and these can be used for serving not only these applications that I just mentioned, but also a large number of different other types of applications. For example, healthcare, space applications and so and so forth. The number is many and you know anywhere that you see there is a problem IoT is quite likely can be used in order to improve the efficiency of the solution to that particular problem. 18 (Refer Slide Time: 28:59) Different other applications such as forest fire detection, air pollution monitoring, snow level monitoring, landslide monitoring and avalanche prevention actually landslide monitoring in our country, there have been different institutions that have already developed systems for landslide monitoring. So, without getting into the details of it, let me proceed further. So, we have earthquake early detection and monitoring seismic system. Seismic sensors have been developed. They can be connected, they can be internet worked and so on. Water leakage monitoring in a water delivery system, water transmission system in a city, radiation level monitoring, explosive exclusive monitoring and hazardous gas monitoring, supply chain control, NFC payment, intelligent shopping applications and smart product management. As I was telling you before you can in fact think of IoT applications in almost any sphere of the society, any sphere of life. 19 (Refer Slide Time: 30:02) So, what is expected in order to build IoT is to have trillions of sensors, billions of smart systems, millions of applications, all of which are going to be internetwork. They are going to be made synchronously operated in order to form, in order to build IoT. (Refer Slide Time: 30:24) Different enablers of IoT in terms of, in terms of enabling technologies, we have from implementations perspective different technologies, such as you know smart homes, smart factories, and so on. Different sensors can be fitted and then, we also have 20 different connectivity offering devices such as RFIDs, Zigbee, Wifi, Cellular connectivity, 6 Lowpan, Lora and so on and so forth. So, different connectivity offering technologies are required and in terms of implementation as I was telling you, factories homes you know banks and transportation sector, agriculture, you know healthcare and so on and so forth, all of these different technologies are required and the other enabling technology is things like big data, deep learning, artificial intelligence, sensor network, regular network, the regular wireless and wired networks. So, all of these are different enablers for buildings IoT. (Refer Slide Time: 31:43) In terms of connectivity, typically there are three layers of connectivity service; service layer, local connectivity and global connectivity. For global connectivity we have the internet, for local connectivity we have components such as the gateway and for service level using different communication technologies, such as these you know different services can be offered to different application areas, such as health care agriculture you know businesses, factories, plants, banks and so on. 21 (Refer Slide Time: 32:24) In terms of the baseline technologies, there are quite a few baseline technologies that can be used. Machine to machine communication is one. In machine to machine communication, one machine directly talks to another machine, communicates with another machine without any human intervention. We have the cyber physical systems where the cyber, the physical systems are basically equipped with computer and connectivity computational and connectivity mechanisms. So, we have a cyber physical system which works hand in hand. Cyber 1, the cyber component of the system works hand in hand with the physical component of the system. So, we have the cyber physical system, we have web of things which is sort of like the web person of the internet of things. 22 (Refer Slide Time: 33:13) So, IoT and M2M, these go almost hand in hand, but there is a distinction whereas, M2M is just concerned about communication and interaction between two machines or two devices using technologies such as cloud regular internet and so on. In the case of IoT, IoT the scope is much bigger. So, in IoT we are talking about not only machine to machine communication, but different other things as well. (Refer Slide Time: 33:48). 23 So, M2M can be construed to be a part of IoT while M2M standards have a prominent place in the IoT standard landscape, however IoT has a broader scope than M2M. So, there can be broader range of interactions and not simply machine to machine interaction. They can be interactions between not only machines and machines things and things, but also things and people, things and applications and people with applications. (Refer Slide Time: 34:23) IoT and web of things, internet of things and web of things are often confused to be one and the same, but there is a distinction. The web of things basically focuses more on the use of web based technologies, such as HTML5, JavaScript, Ajax, PHP and so on and so forth. 24 (Refer Slide Time: 34:51) (Refer Slide Time: 34:53). Over the regular IoT to make IoT smarter and web accessible, there are a lot of terminological interdependence when we talk about IoT. IoT has similarity with internet of people which has a people focus IOP from IoT different using IoT different industry oriented machines and so on can be controlled. So, we have smart factories, you know smart factories using a robots virtual reality and so on. One can have industry 4.0 which is an approach to the modern day mechanization or improvement of the current day plans and industries. 25 Internet of environment is another. We have CPS which is basically the Cyber Physical Systems, where these systems basically autonomously they operate and they can in fact in an IoT world what can happen is these CPS systems, these different CPS systems, they can be internetwork together in this particular internet. That means, the internet of things we have M2M machine to machine communication. I already mentioned to you maybe what can happen in a smart home machines, such as the lighting system can talk to the cooling system directly, the cooling system can talk to, can communicate with the fans directly, the fans can communicate with a mobile phone directly or the mobile phone can communicate with a fan directly. So, as you can see that between two different machines, without any human intervention, you know communication can take place and this is known as M2M. So, with this we come to an end of this particular lecture and we are going to continue with the introduction in the next part of the lecture as well. So far what we have understood are the basics of internet of things, the motivation behind internet of things, the different application areas, the different main points, the challenges that are involved and what we are envisioning when we are talking about building internet of things in the future. Thank you. 26  Introduction to Internet of Things Prof. Sudip Misra Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture - 02 Introduction to IoT-Part- II So, now we are going to continue in this lecture with the other basic instructions Basics of Internet of Things. (Refer Slide Time: 00:34) So, we have already seen that in the future, it is estimated that the number of things are going to be many, the number of internet of things that are going to be connected are going to be many. So, it is estimated as per one of the studies that by 2018, almost we are going to have 20 to 50 billion devices that are connected that are going to be internetworked. So, many different applications, so many different devices and these devices are going to be made smart in these applications. So, that is the reason why we are going to have an explosion or in the number of these internetwork things, number of devices connected to the internet of things. So, as we can understand that if you want to internetwork, if you want to form a network, a big network, a joint network of internet of things, that means these things being 27 connected, then one fundamental problem that is going to happen is there is going to be an address crunch. We are going to soon run out of the number of addresses that we can assign to each of these devices, the different addresses for example the IP address and so on. So, IPV4 is defiantly not good enough. People have explored the use of IPV6, but what is required is to come up with a completely new type of addressing scheme which can take care of these issues because of this address crunch. The next thing is the connectivity. At present there are different various sources, different various ways of offering connectivity. Cellular is one Wi-Fi Ethernet, then Bluetooth Low Energy, Dash 7, Insteon, IEEE 802.15.4, 802.15.6, 80.2.16 so and so forth. So, many different connectivity mechanisms, connectivity standards are available. So, this is going to be another challenge with respect to network. So, how you are going to have some kind of handshaking between each of this different isolated standards. So, this handshaking has to be, handshaking mechanism has to be devised. (Refer Slide Time: 03:08) So, in terms of connectivity, we are talking about concepts called Unique Building Blocks, such as the LAN IoT, WAN IoT, Node IoT, Gateway IoT, Proxy and so on and so forth. So, all most analogist to what we have as different components of the internet, the capital I internet means the internet of computers analogously. We are also going to 28 have these different components, the LAN, the WAN, the Node, the Gateway, the Proxy, these different components. So, the concepts are very similar as we have in the internet. So, IoT LAN is very similar to IoT, the internet LAN. So, this is for Local Short Range communication may be building wide or campus wide and so on. IoT WAN is basically internetworking of two different LANs, you know inter connecting of two different LANs, connecting different various network segments organizationally or maybe geographically wide and these can be connected to the internet IoT Node which is the connectivity of the different Nodes inside a LAN or maybe a WAN also directly. Sometimes the LAN you know, the Nodes in the WAN can also be connected IoT. Gateway is basically sort of like you know a router or something very similar which connects to the IoT LAN. So, it is sort of like the outside world, the Gateway beyond a LAN and typically connecting to the WAN. So, we can have in WAN, you know several LANs connected to each other through the individual Gateways and Proxy very similar to what we use proxies for security proxies for sub networking and so on. (Refer Slide Time: 05:15) So, if you look at the first picture over here, what we see is IoT LAN. So, you know IoT LAN we have this different IoT devices and each of these devices has its own unique address, local address and these addresses are local uniquely uniquely local. So, unique that what I am trying to say over here is within a particular LAN, these addresses are 29 unique, these local addresses are unique and similarly, within another LAN, IoT LAN these addresses are unique. So, these are locally unique addresses. So, it might so happen that a particular address might be unique to this LAN, but may be reused in another LAN. So, the other thing is that these two different LANs, they can connect via two different Gateways. These are the Gateway Nodes and also, we have seen that there is a concept of Proxy. So, Proxy basically helps connects to connect to the external internet. So, Proxy helps to connect to the internet. So, it is beyond the Gateway and connecting to the internet that is offered by the Proxy. (Refer Slide Time: 06:56) So, some of the IoT network configurations are restricted to local areas, very analogous to what we have as internet LANs, WANs and Proxy and this is what we have seen in the previous figure. So, the Nodes that are within the Gateways jurisdiction have addresses that are valid within the Gateways domain only and the same address maybe repeated in another domain as I was telling you before in the previous slide in the previous diagram. So, the Gateway has a unique network prefix which can be used to identify them globally. So, there is a unique network prefix as well and we are going to look at it shortly. So, this strategy basically saves a lot of unnecessarily address wastage and although the Nodes have to communicate to the internet via the Gateway. 30 (Refer Slide Time: 07:50) So, for address conservation as we have seen, these addresses are unique locally, but they can be reused in another domain, but these networks are connected to the internet, these IoT networks are connected to the network through the Gateway and these IoT routers the network is connected to the internet and these are connected through the routers and these have their own set of addresses and ranges and that means the address ranges. So, these routers have multiple Gateways and they are connected to them which can forward packets from the Nodes to the internet only via these routers and these routers assign the prefixes to the Gateways that are under them. So, we have this prefix 1 and prefix 2, two different prefixes that I used that are assigned by their corresponding routers to the Gateway. So, prefix 1 is assigned by this router to this Gateway and prefix 2 is assigned by this router to this particular Gateway. 31 (Refer Slide Time: 09:11) Now, this is a very important concept that has been proposed because it helps to solve the problem of mobility. So, basically what is going to happen is when a particular Node changes its position from a particular network to another network, let us say from this network is Node moves and comes to this particular network, then the prefix is also going to change from 1 to 2 and this is going to make the IoT LAN safe from changes due to mobility. So, IoT Gateway, basically the IoT Gateway WAN takes care of the address changes without change in the LAN address. So, within the LAN, the address remains the same, but with the help of assignment of this unique prefix, the WAN address changes and that is how the mobility addressing aspect of mobility is taken care of. So, in this particular figure, we see that there is this concept of the remote anchor point and these particular entity in this network is the one which has the global view of the network that is underneath. That means, this entire network comprising of these LANs, this WAN, the Gateway, then this thing routers and so on. So, this particular entity is considered to be the one which has the unique global view of this network underneath. 32 (Refer Slide Time: 10:54) So, now let us try to understand few other concepts surrounding it. So, we have already seen that there is a remote anchor point and if there is a change in the network prefix that can be taken care of automatically and technologies or protocols, such as mobile IPV6 can come helpful in this particular scenarios assuming that IPV6 based addressing is being used. So, within a particular LAN, the address of the Nodes remain unchanged because they are within the Gateway and so within the Gateway, there is a local unique address and the change in the Gateways network prefix does not affect them, but it might be required for the Nodes to communicate directly to the internet as well and this can be done with the help of concept of tunnelling where the Nodes can communicate to a remote anchor point instead of channelling their packets through the router. This can be done with the help of tunnelling protocol, such as IKV, IKEV2. So, this is how with the help of IKEV2, this tunnelling can be done with the help, with the remote anchor point through the Gateways. So, indirectly from the Gateway to the anchor points, the tunnels can be set up like this. 33 (Refer Slide Time: 12:25) The Gateway has you know associated, they can come with or without proxies and they can offer internet connectivity or intra LAN connectivity. So, within the LAN, they can offer connectivity between the different Nodes within it so for up upstream addressing, that means beyond the Gateway. So, Gateway to the internet mechanisms, such as DHCPV6 assuming that IPV6 technology is being used, DHCPV6 for state based addressing or SLAAC for stateless addressing can be used and the locally unique addresses are maintained independently of the globally routable addresses in cases were internal address stability is of prime concern. 34 (Refer Slide Time: 13:21) So, we have to keep another thing in mind that despite this mechanism of address stability, the LU cannot communicate directly with the internet or the upper layers which is solved by implementing an application layer Proxy. So, this proxies basically help in achieving connectivity to the upper layers on the internet. (Refer Slide Time: 13:50) So, most of the IoT based solutions at present still are using IPV4. There are very few IPV6 implementations. So, what is going to happen is if you want to deploy, if you want 35 to approach building IoT by expanding the existing internet, they approach one that I talked about initially as part of lecture 1 for building IoT. So, in that particular case, what needs to happen is there are different addressing schemes that are followed IPV4 IPV6 and so on. So, something like address translation between IPV4 and IPV6 and vice versa has to happen. This is one until we have a separate addressing scheme, a new type of a addressing scheme. So, handshaking or translation of addresses from IPV4 to IPV6 or from IPV6 to IPV4 number 1, number 2 is tunnelling of IPV6 over IPV4. So, maybe some part of the network uses IPV6. So, these IPV6 PD used can be tunnelled over IPV4 PD used application layer proxies can also be used and these can help in achieving tasks such as data relaying. (Refer Slide Time: 15:21) Finally, I would like to mention that there is a concept of multi-homing, where a particular Node or an IoT device or the sub network, IoT sub network can be connected multiple networks for improving the reliability. So, basically multi-homing is a concept that is used for improving the overall liability of the network in that way. So, in the same state if some component of the network or maybe a Node has gone down, there is another network that can take over. So, for these multi homing, there can be two different approaches; a Proxy based approach can be used or a Gateway based approach. I do not need to explain these two 36 approaches in detail, but these names basically tell how the things are going to be managed for multi-homing using these different approaches. (Refer Slide Time: 16:16) So, providing source address, destination address and routing information to the multi- homed Nodes is the real challenge in multi-homing networks. So, presently IETF is trying to standardize this particular issue. (Refer Slide Time: 16:32) So, IPV4 is being used, some parts IPV6 being used. We can use both, but that is not going to be sufficient. We have to come up with a new addressing scheme which we do 37 not know yet what is going to happen. People are still working on it, researches are coming up with different mechanism. There are still lot of research effort on building addressing schemes for IoT, but if IPV4 is used and IPV6 is used, these are the comparison points of comparison between the use of IPV4 and IPV6. The main point of difference is that because the bit length, the length over here in IPV4 is 32 and in IPV6 is 128, the number of addresses in IPV4 is S2 the power 32 only. On the other hand, the address space over here is 2 to the power 128. So, we are going to get a large address space and I think we already know that there is a difference in the notation in IPV4 which is dotted decimal notation and it differs from the IPV6 which has a hexadecimal notation for addressing. (Refer Slide Time: 17:49) 38 (Refer Slide Time: 17:55) So, here are few other points of comparison which I am not going to go through and here is the IPV4 header format. (Refer Slide Time: 18:01) 39 (Refer Slide Time: 18:06) Here is the IPV6 header format. So, these IPV4 and IPV6, they have to go hand in hand until there is a new solution for addressing a new mechanism which is completely different from these proposed. So, they have to work hand in hand. So, you know mechanism such as tunnelling or address translation mechanisms have to be used in order for this thing to happen. So, with this we come to an end of introduction on IoT Internet of Things. We have already understood the motivation for building IoT systems, the different applications of IoT systems, the different characteristics of IoT systems, the different challenges that are involved from networking prospective, what are the different components for building IoT. IoT is a joint network, but then you have to use a modular approach, a step by step approach, a phased approach to building IoT. So, what are the different components from a networking prospective that can be used is what we have already gone through and we have understood. So, with this we come to an end of the lecture on the Introduction of Internet of Things. Thank you. 40  Introduction to Internet of Things Prof. Sudip Misra Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture - 03 Sensing So, we have already understood the basics of internet of things. Now, let us try to understand that what are the essential building blocks of internet of things. So, one of the very essential components of internet of things is sensors and the other one is actuators whereas, the sensors basically sense the physical phenomena that are occurring around them and the actuators basically based on the sensed information. The actuators, they actuate. That means, they perform some actions on the physical environment. So, they take some actions based on what has been sensed. So, essentially if we see that we have a gradual phase wise approach to building internet of things. So, we have sensors which are sensing the sensors, they sense different parameters depending on the sensor being used. For example, temperature, pressure, humidity conditions, lighting conditions and so on. Then, what will happen is these sensed information are going to be sent over a connected system. That means, over a network that information will be passed, it can also involve cloud and so on and finally, that information is going to be transmitted based on what has been sensed and based on the requirements, some physical action is going to be taken by an actuator. So, may be a bulb might be turned on if certain conditions, in an agricultural field has happened, maybe if the field based on the sensors it is found out that in an agricultural field, the field has run out of stagnant water that is required for paddy crops. Then, what might be required is based on that sensed information automatically the valve of the water pump, the deep to well that is used or a shallow tube well that is used for irrigation, automatically that valve will be turned on, so that the field gets irrigated. So, that can be done through the process of actuation. So, we have sensing. we have IoT or simply the network and then, we have this actuation. So, sensing network actuation we start with the sensing component. Now, in the next lecture we will try to understand how actuation is done. 41 (Refer Slide Time: 03:17) So, when we talk about sensing, we need to understand what is sensing. So, basically a sensor it detects or senses the changes in the ambient conditions or it can also sense the state of another device. So, maybe one sensor can check, can sense how and what is the state of another device. So, this is what he is done with the help of sensing. So, some physical property of the ambient conditions of the environment in which the sensor is in or of another machine or a system a separate one, these can be sensed with the help of sensors. So, let me now show you some sensors, some real sensors that we have. 42 (Refer Slide Time: 04:06) So, here are few real sensors and this is a sensor that is used for obstacle detection. This is a PIR sensor passive infrared sensors. So, this passive infrared sensor here can be used for detecting if there is any obstacle. So, this is an example of a PIR or obstacle based sensor. (Refer Slide Time: 04:45) Then, we have another sensor this is the ultrasonic sensor. This basically detects that how far that obstacle is. This is another sensor. So, here as you can see that there are like two eyes kind of things. So, what happens is these ultrasonic sensors may send 43 ultrasound waves. So, these ultrasound waves are sent and then, that sound wave is going to get reflected back. We already know what velocity is and then, depending on how much time has elapsed from the point sound wave was sensed and the deflection is received back, based on that the distance is calculated. So, this sensor helps in basically getting an idea or sensing how far an obstacle is from a particular point where the sensor is. (Refer Slide Time: 05:46) Then, we have another sensor which is the camera sensor. This is as you can see over here is small IoT camera. Since the camera sensor, then we have this one here which is a smoke detection sensor. So, this sensor can help in detecting the smoke. 44 (Refer Slide Time: 06:08) Finally, I would like to show you another sensor which is the temperature and humidity sensor. This is actually, this measures both of these together this particular sensor. (Refer Slide Time: 06:23) So, these are some real life sensors, real examples of sensors that I have just shown you like this. There are different sensors that can be purchased. These sensors, they have different functionalities and these functionalities are typically unique. That means that one sensor which is fabricated to do, to measure a certain physical property, it cannot 45 measure another one or more specifically let me give you an example to illustrate this point because this is something that many people make a mistake. So, a temperature sensor can measure temperature only. It cannot measure for instance smoke or it cannot detect smoke. So, these are very much application specific you know specific things, specific properties, basic specific physical properties can only be detected by these sensors. Now, the sensors they come in different shapes and sizes. They can be very small, they can be very big. The same sensors can be mechanical sensors, these can be electrical sensors, they can be electronic sensors, they can be chemical sensors. There are so many different types of sensors and fabrication of a sensor is a completely different ballgame. So, whether it is a mechanical sensor or an electronic sensor, electrical sensor or you know a chemical sensor, whatever it is a completely different ballgame. Typically people who are into building of IoT, they focus more on the networking aspects. They focus more on the networking analytics aspects of IoT. There are separate researchers who work on the design of these sensors. Some of these sensors that I have just shown you, the sensors you know that complete the design, the fabrication it is a completely different story altogether you know. So, you know this is and typically this is done by those who are focusing on sensor design and fabrication. So, typically they are concerned only about how these sensors can be developed, they can be fabricated and they are not bothered about building IoT as such. Of course, there can be some researchers who might also take interest sensors. You know not just the fabrication of the sensors, but also going beyond building of the IoT. Some people might be taking interest in that, but in general it is not. 46 (Refer Slide Time: 09:22) So, the sensors based on certain stimuli, the different stimuli might be there. They can measure the thing in the physical characteristics of the environment of the system and so on and these changes are basically converted to electrical signals. For example, for a heat sensor this heat is converted to electrical signals and this is for temperature sensors. I am sorry, this for temperature sensor, the heat is converted to electrical signals and for sensors such as atmospheric pressure sensors, the atmospheric pressure is basically converted to electrical signals. So, we have different sensors which measure different things, but then these sensed values are converted to respective electrical signals. (Refer Slide Time: 10:30) 47 Now, there is an associated terminology which is for the transducers. The term transducers basically convert one form of energy into another form of energy being converted into another. For example, in a microphone what we have in a microphone. So, the sound waves are converted to electrical signals and then, to a output device like a loudspeaker and we are able to hear that sound. So, this is an example of a transducer. (Refer Slide Time: 11:09) So, these terms sensors and transducers are very common. They have lot of overlap and we have to understand the distinction between these two. There is lot of misunderstanding people conceived sensors and transducers. We use these terms almost interchangeably, but there are differences. So, the word transducer is a collective term which includes sensors as well as the actuators that I was telling you. Before the sensors can sense what is going on around them and convert to electrical signals etcetera and the actuators can basically perform these actions by maybe switching voltages or currents. 48 (Refer Slide Time: 12:00) Now, the sensors have different features. They are sensitive to the property, the physical property that is being measured. So, they can do all. They are sensitive only to that measured property. So, basically a temperature sensor can sense only the ambient temperature of the room and it is insensitive to other changes, maybe changes in the atmospheric pressure or changes in the lighting condition of that room. (Refer Slide Time: 12:31) There is a terminology which is called the resolution. The resolution of a sensor is basically defined as the smallest change that it can detect in the quantity that is being 49 measured. So, the smallest change that it can detect the resolution of a sensor with a digital output is usually the smallest resolution of the digital output. It is capable of processing. (Refer Slide Time: 12:54) So, based on the output, the sensors can be classified as analog or digital and based on the data type, they can be classified as scalar or vector sensors. So, in the analog sensor, what we have these sensors give continuous analog output. So, for example, tint temperature sensor continuously changes in the temperature are going to be sensed, measured and the output is going to be an analog signal. Digital sensors basically gives digital outputs on and off for example, and like this come you know discrete digital values are given as outputs by these digital sensors. Then, scaler sensors basically measure scalar variables which can measure only the changes in the magnitude whereas, the vector senses not only the magnitude, but also the direction. So, scalar sensor example would be temperature sensor is an example of scalar sensor because you know irrespective of which orientation you put, the sensor temperature sensor or in which direction you are taking it, it is going to give you the magnitude value. Only the changes in the magnitude of the temperature, on the contrary we have the vector sensor. For example, the camera sensor or the accelerometer sensor whose values are dependent on the orientation on the direction and so on direction in which the sensor is being put and the weight is measuring. So, it is dependent on that. So, 50 we have analog sensors, we have digital sensors, we have scalar sensors and we have vector sensors. (Refer Slide Time: 14:44) So, analog sensor I already mentioned about analog sensors, temperature sensor. You know temperature is typically measured with the help of thermometer or thermocouple thermometers are quite common, but thermocouple is something that is used in the geezers for example, you know. So, you have two different metallic strips for instance and these strips they know they can, in the thermocouple they can bend and so on. So, these based on that you know based on the amount of bending etcetera. You know they measure the changes in the temperature. So, if you calibrate the thermocouple you know, so accordingly it is going to give how much the temperature has changed and depending on that one can understand how much the liquid has heated up or has cooled down. 51 (Refer Slide Time: 15:36) Digital sensors produce digital discreet voltage levels or signal levels. So, binary values like 0 and 1 or on and off or output the digital sensors. (Refer Slide Time: 15:53) Scalar sensors measure only the magnitude physical quantities, such as temperature, color, pressure, strain etcetera. These are scalar quantities and measurement of the change of magnitude is sufficient to convey the information. 52 (Refer Slide Time: 16:13) On the other hand, vector sensors produce output signal of the voltage which is generally proportional to the magnitude as well as the direction and orientation of the quantity that is being measured. So, physical quantities such as the sound, image, velocity, acceleration orientation, these are all vector quantities and their measurement is not just dependent on the magnitude, but also on the direction. So, for example, accelerometer sensor, they give outputs in three dimensions x, y and z coordinate axis. (Refer Slide Time: 16:50) 53 Here are some examples of different sensors, light sensor for measurement of light. We have the lDR which is the light dependent resistor photodiodes. This can act as sensors for measurement of light for sensing of light. For sensing of temperature, we have thermistor and thermocouple. Thermocouple briefly I told you, but thermistor is sort of like thermal transistor kind of thing, ok. Then, we have for force, we have the stain, strain gauge and pressure. Pressure switch for position, we have potentiometers, encoders, opto couplers. Opto couplers basically you know. So, the optical signals are the optical rays are basically obstructed and based on that you know the position information can be obtained. So, opto couplers then we have the speed for speed sensing. We have reflective sensors, then doppler effect sensors. So, doppler effect based on the relative velocity for example relative velocity of sound you know. So, based on that you know this doppler effect sensors, they work. Then, we have the sound sensors, we have the carbon microphone like our existing traditional microphones, piezoelectric crystals and so on. For chemical sensing, we have the liquid chemical sensors and gas chemical sensors. (Refer Slide Time: 18:18) So, I had already in at the outset of this lecture, I had shown you some real physical sensors. Here are some other pi pictures of few other sensors, here is a pressure sensor, here is an ultrasonic distance sensor, tilt sensor infrared motion sensor, camera sensor, analog temperature sensor. So, analogs in temperature sensor, it has you know in 54 addition to the output, it has 2. So, it has three pins. Basically one is for the plus 5 volts and the other one is the ground zero volts and this one is the middle pin is typically used for the output. (Refer Slide Time: 19:04) Now, the sensors often they do not give data that is accurate you know. So, there are some sensorial deviations. So, these sensors they have each sensor and they come with certain specifications. These specifications will give you the maximum and the minimum values that it can measure of the physical property that it is supposed to measure. The sensitivity of a sensor under real conditions may differ from the value that is specified and that is known as the sensitivity error and then, each sensor there can be given you know a value which is constantly the same, constantly different. So, what I mean by this is the correct value might be something and always it will be giving this particular sensor, might be giving a value which is an offset error or a bias and that might, so that many units of offset error reading will be giving at all times and that will be constant. So, for example, two units of offset might be given by a temperature sensor at all times. So, that is different from the sensitivity error that I told you. So, sensitivity error is more about being sensitive to the changes you know under real conditions, basically how it is being sensitive. Then, what is specified in their actual specifications, it might give certain actual specifications, it might suppose give certain values, but in real conditions, it might be sensitive to certain things. So, this becomes the 55 sensitive error and there will be some error that will be due to that and that sensitivity error that can change over time and that is different from the offset error which is constant over time. (Refer Slide Time: 21:17) Now, these sensors typically have linear behavior. Most of the sensors, not all have a linear behavior, but there is often in practice a non-linearity behavior that is exhibited by the sensors and ideally they should behave linearly, but in practice stays off will behave non-linear. So, this non-linearity is the deviation of the sensors transfer function from linearity. So, this is basically defined as the amount of the output that differs from the ideal transfer function behavior over the full range of the sensor. 56 (Refer Slide Time: 22:09) So, if the output signal slowly changes independent of the measured property, this is known as drift. So, it might happen that a particular sensor at one point we give a certain value and then, if you use the same sensors for measuring the same condition due to the drift, you might get a drifted sensed value. So, it will be different; it might be different. So, it induces some drift if you keep it overtime. So, the other type of error is the noise which is basically due to different other external factors and it is a random deviation of the signal with time. (Refer Slide Time: 22:52) 57 Hysteresis error is bit different and typically it is exhibited by analog sensors, magnetic sensors heating of in sensors that use the principle of heating of metal strips and so on. So, in these sensors, these analog sensors or magnetic sensors and so on sometimes what happens that the present reading depends on the past input values. How? It is maybe because it uses some metal strips and maybe the property or the functionality of that sensor is such that when you heat it, it is going to the metal strip is going to bend. So, so you know if it has bent once to come back to its original position, it will take some time. So, this type of error basically talks about that you know if it is heated once you will get something. So, based on that if you heat it once again, you know your output is going to be dependent on the previous value. So, this is an error and this is known as the hysteresis error. (Refer Slide Time: 24:06) There are different other errors, such as quantization error which is basically if the sensor has a digital output, the output is essentially an approximation of the measured property and this is known as the quantization error. If you are sampling the signals, this leads to a type of error which is known as aliasing error and the sensors may at times be sensitive to the properties. Then, the property that is being measured for example, a temperature sensor might also sometimes be sensitive to few of the other things that are not directly being measured, maybe you know the humidity or pressure at times or maybe light, this will depend actually I mean this is not a perfect example that I have given you. So, it can 58 be constitute, this particular error can be constituting this way that sometimes the physical property that is being measured that may get affected, that sensor may get affected by few of the other properties that are not directly being measured. So, this also leads to some kind of error. So, with this we come to an end of the topic of sensors. So, here we have already seen that there are different types of sensors and I have shown you some real life sensors that can be used for building of internet of things. I have also shown you pictures of many other sensors and these sensors are used in something known as the sensor nodes. The sensor nodes are eventually going to get connected, they are not going to be networked together, internetwork together and together that is going to form an internet of things and this internet of things is going to be used for improving the overall service quality in the society of the business of the environment as a whole. Thank you. 59  Introduction to Internet of Things Prof. Sudip Misra Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture – 04 Actuation So, this particular lecture is on actuation. So, based on the readings of the sensor, we have already seen different types of sensors in the previous lecture and based on the readings of these different types of sensors, some action might be required to be taken and that is done by actuators. These actuators basically perform certain actions on the environment on another system on a device and so on. So, there are different examples of actuators. I am going to show you a different type of actuators very shortly, but these actuators, they can have principle of working principles which are based on electronics, then electrical, then you know mechanical systems and so on. So, they basically you know use some kind of control behavior, some control signals are sent. So, this is how these actuators, they perform. We are going to go through the different mechanisms behind the functioning of these actuators in this particular lecture. (Refer Slide Time: 01:37) 60 Before we proceed, I wanted to show you at the outset some of these actuators that can be used. So, here is an example of a sample actuator which is known as the relay switch. So, this relay switch, it is an electromechanical switch which can be used to switch between AC and DC for instance or different other things can be performed. So, the sensor networks, the sensor nodes, they typically operate in DC and based on the sensed value maybe you know you want to switch off the electricity in your room or at your home based or maybe something, maybe fire has been detected by the sensor network, then you want to do something or you want to turn off the power in your home. So, that is AC that operates on AC, right. So, this particular switch, this electromechanical switch will basically turn off AC that the power supply at your home. This can help in doing it. So, this is an example and this is known as relay. (Refer Slide Time: 02:50) There is another one which is the solenoid valve and this basically can help in controlling the flow of liquid. So, you have an input; you have an output. So, we have an input, we have an output and the solenoid valve if we open it, so what we can see over here is what is inside. So, you know water can flow in and depending on the conditions, this valve is going to either allow the water to flow out or it is going to stop. It is not going to allow. So, this is another actuator. Like this there are different actuators that are available for use in IoT. So, having seen some real life actuators, let us try to understand the basic principles of actuators, but before that let us go through some of the basics. 61 (Refer Slide Time: 03:52) So, an actuator is a component of a machine or a system that moves or controls the mechanism of the system. So, typically these actuators are based on some control system and these control systems, they act on the environment. So, an actuator basically requires some kind of a control signal and a source of energy for their functioning. (Refer Slide Time: 04:28) So, typically I said that control signals are required for the actuators. So, when these actuators receive a control signal, they respond by converting that energy into mechanical motion. Some mechanically something is going to be done. This is an 62 example of course. So, they convert that electrical signal, some control signal into mechanical motion and that control system can be simple which can be based on some mechanical or electronic system or it can be software based like a printer, driver, robot, control system, a human or any other input. So, what we have are three types. Three types of actuators, one of actuators, one is these electric based actuators. We have this pressure based actuators and we have these mechanical based actuators. Each of these, they send control signals and based on that the actuation is going to be performed. (Refer Slide Time: 05:33) So, we have hydraulic actuators, pneumatic actuators, electrical actuators, thermal actuators, magnetic actuators and mechanical actuators. 63 (Refer Slide Time: 05:44) So, this name suggests, these hydraulic actuators consist of a cylinder or fluid motor that uses hydraulic power to facilitate mechanical operation. The mechanical motion is converted to linear rotary or oscillatory motion. So, basically you know when some fluid passes through, then you know that motion is converted to some linear motion or some oscillatory motion or rotary motion and since liquids are nearly impossible to compress, most of the hydraulic actuators basically exert considerable force. So, that is the reason why liquid based actuators are typically used you know. So, these are quite popular because of this particular reason. 64 (Refer Slide Time: 06:36) On the left hand side, we see an example of an hydraulic actuator which is based on the use of oil. So, in this particular cylinder, oil will be there and then, when you put, when you apply pressure on it, it is going to give an output based on which there can be some linear motion or some oscillatory motion or rotatory motion or whatever that can be performed. So, here on the right hand side, we see over here a figure which shows an hydraulic actuator based an hydraulic actuator, based on radial engine. So, as we can see over here, this is quite. This animation is quite. You know it is quite explanatory. So, as we can see over here you know liquid goes inside and when you synchronize the liquid going inside from these different directions, then what happens is you can emulate a rotatory motion like this. So, this basically can help in the functioning of an engine. So, it can give a rotatory motion in this manner. 65 (Refer Slide Time: 07:51) So, those were the hydraulic actuators. Pneumatic actuator, pneumatic means air based. A pneumatic actuator basically converts the energy formed by vacuum or compressed air at high pressure into either linear or rotatory motion. So, you know the rack and pinion actuators are typically the pneumatic actuators and these are used for valve controls of water pipe, water pipes. Pneumatic actuators basically exert a lot of force and for example, the pneumatic brakes can be very responsive to small changes in pressure that are applied by the driver. (Refer Slide Time: 08:22) 66 So, pneumatic brakes are quite common in different like trucks etcetera. They use pneumatic brakes. So, hydraulic brakes are more common in cars, in trucks. The pneumatic brakes are quite common. So, these pneumatic brakes, the advantage is that they are very responsive to small changes. You know if the action, if the brake is pressed little bit, you know they become, they act quite fast. This is an advantage of these pneumatic actuators. So, basically what happens is the pressure that is put on the brake that is converted into force pretty fast. So, this is one of the advantages of these pneumatic sensors. (Refer Slide Time: 09:16) So, here is a figure of a pneumatic sensor when you apply pressure over here. So, this shaft, this crankshaft or this shaft will move and this is an example of a pneumatic actuator. So, basically this is a figure which shows an air pump acting as a pneumatic actuator and then, we have seen hydraulic actuators, we have seen pneumatic actuators. 67 (Refer Slide Time: 09:40) Then, we have the electric actuators. An electric actuator is generally powered by a motor that converts electrical energy into mechanical torque. So, this electrical energy is used to actuate the equipment, such as the solenoid valve which control the flow of water in pipes in response to electrical signals and this is what I was showing you at the outside. I showed you one of the actuators. The solenoid valve I had shown you and this basically works on the principle of electrical actuator. (Refer Slide Time: 10:19) 68 So, on the left hand side is a figure showing a motor drive based rotary actuator. So, basically you know what happens is this basically you know the electrical signal over here will help in moving this. So, it is going to give a rotary motion of this particular part. So, this is an example of a motor drive based rotary actuator. Here in this particular animation what you see is an electric, the functioning of an electric bell. An electric bell is an example of a solenoid based actuator. So, as you can see over here once the bell is pressed, then the connectivity is established and then, the electromagnetic field is generated due to which the bell sounds and this is the way in which solenoid based electric bells functions. So, these are two examples of electrical electrical actuators. (Refer Slide Time: 11:39) Then, we can have thermal or magnetic actuators which can, so thermal or magnetic actuators, these can be actuated by applying thermal or magnetic energy and typically, they are very popular because of being that they are very compact, lightweight, economical and with high power density. So, these active actuators use shape memory materials or shape memory alloys SMAs and this is very popular at present. 69 (Refer Slide Time: 12:12) So, this is how it works. So, this is an example of an SMA based piezo motor. So, as you can see over here, these are the different steps in which it works. So, these are two metal strips and when you know when the energy is passed through it, they bend and when they bend, they basically move this red and white strip mechanically. So, this basically acts as an actuator. So, this is like a joint metal bar and this is like this, sorry. So, when you heat this metal bar, this is an alloy bar consisting of two metal strips. So, you know the property is that when you heat it, then it is going to bend and when it bend, it is going to move this particular strip in this manner. So, the different steps are shown over here and this is quite evident, it is quite explanatory from these steps. 70 (Refer Slide Time: 13:30) So, this is an example of a coil gun which basically works on the principle of magnetic actuation. So, this is also quite explanatory. So, this coil gun you know. So, basically you know electromagnetic field is generated and then, you know again it is pushed and so on. So, basically you know functioning of the hyper loops, at present people are talking about hyper loops, right. So, presenting if the functioning of the hyper loops are also you know based on this particular principle. (Refer Slide Time: 14:05) 71 Then, we have these mechanical actuators which basically converts rotatory motion into linear motion to execute some movements. So, this basically involves these gears, the pinions, gears, pinions rails, pulleys, chains and other devices to operate. So, rack and pinion is an example of a mechanical actuator. The figure shows it and it is quite exponentially from this. (Refer Slide Time: 14:34) So, as it moves, basically this also moves. So, a crankshaft is another example of a mechanical actuator. So, this is how the crankshaft works. (Refer Slide Time: 14:54) 72 So, as this thing moves in this manner, so this gives this one a mechanical motion, a rotatory motion. There are different soft actuators which are actually polymer based and the design to handle fragile objects like fruit harvesting in agriculture or in biomedicine, handling internal organs of human beings and typically these are used in robotics. So, soft actuators are also quite popular. (Refer Slide Time: 15:16) These basically use something known as SMP, the Shape Memory Polymers which are actually polymers and the behavior of the polymers will change depending on the stimuli. The stimuli for these polymers are the light, electrical signals, magnetic signals, heat, PH etcetera. They have different properties. These polymers, they behave differently due to these different variations in these physical properties. 73 (Refer Slide Time: 15:43) Then, we have the light activated from polymers. These polymers basically get activated through light stimuli and these are also quite popular. So, what we have seen are different actuators, their actuation principles and different diagrams and figures of them and at the outset, we have already seen some real actuators that can be used for building IoT based systems. Thank you. 74  Introduction to Internet of Things Prof. Sudip Misra Department of Computer Science & Engineering Indian Institute of Technology, Kharagpur Lecture – 05 Basics of IoT Networking-Part-I In this lecture and a subsequent few, we are going to go through some of the basics on the networking aspects of Internet of Things. (Refer Slide Time: 00:35) So, the first thing that we need to understand is that IoT has evolved a lot. So, starting from basic research, basic fundamental research and innovation, there has been different other types of innovation which are done through, which are disruptive, and some of the other innovations which are sustaining in nature. So, in terms of basic research, there has been a lot of research on the nanotechnology, the use of nanotechnology, the use of quantum teleportation. Quantum teleportation basically means that how the different information at the atomic level is sent from one point to another. So, it is transported from one point to another at the atomic level and nanotechnology, it involves things like nano IoT, nano nodes, nano networking, nodes, nano sensor nodes and nano networks. That means, at the nanoscale forming a network which can be for different purposes, nano networks are used for different purposes in the human, inside the human body at the molecular level nano networks can be used. So, like this at the 75 nanoscale and for quantum communication, there has been lot of advertisements that has been done for involving basic innovations, basic research innovations. So, this is one likewise for semantic interoperability. There has been lot of research on semantic in for interoperability. For example, let us see that a temperature sensor, it might be given the data as temp, another temperature sensor as temperature, another temperature sensor the third one. So, there has to be interoperability between all these different collisions, but they are all different to the same temperature, right. So, this is basically taken care of by things like semantic interoperability. There has been lot of research on this one, this particular aspect then energy harvesting. Again there has been lot of research, you know energy harvesting through different renewable sources such as wind energy, solar, etcetera. How these can harvest, you know how these deferent renewable sources from these how energy can be harvested to power the different nodes and IoT, these are very small powered you know small sized nodes with very limited power. So, energy harvesting is very crucial. It plays a crucial role in the sustenance of these networks. So, there has been lot of work on this one also and this has been like you know these aspects for example, there has been lot of brick through innovation on these. Then, disruptive innovation for example virtual reality, augmented reality you know. So, these are all like you know involvement of these incorporation into the IoT network, there has been lot of research on this particular front and things like cloud big data, these are like sustaining technologies for IoT. Again there has been lot of work on these technologies as well. 76 (Refer Slide Time: 03:59). Now, when we talk about IoT, if we think about IoT, what we have? We have these different things which as I said in one of the previous lectures is these things are fitted. These are basically physical objects once again. So, these physical objects are fitted with different sensors and these sensors basically sense different physical phenomena that are occurring around them. So, these sensor fitted things, sensors actuators and different other emirate devices, these are one component of the IoT, but these become different nodes in the network, these are the individual nodes in the network. So, then what we have is, these nodes they have to communicate with one another and the information that is sensed by one of these sensors fitted to these nodes, this information from the sensor and the other sensors, these are taken and are sent to the other sensor nodes, the destination nodes. So, how is that turn? First this information has to flow through the local network and then, if the destination, intended destination is outside this local network, then it is sent through the internet. Typically if we are talking about an IoT which is basically internet based IoT, then basically it is going to flow through the internet or some other wide area network and finally, it is going to arrive at the intended destination node and may be there can be some at that point, actually there can be some analytic engine which is running on some backend server, those could be there and from that point from the decision, from these analytics, they can run on these servers decisions about actuation could be made. 77 So, what we see is from sensors to actuators through the local area network, the internet involving you know backend services analytics which includes again some you know high end processing at different servers and different complex algorithms, execution of different algorithms which are based on may be machine learning neural networks and so on and so forth. These are all required. So, basically you know what happens is we basically can conceive an IoT as a very complex system involving sensors, actuators, networks, local area, wide area internet and different servers, different algorithms, machine learning and so on, all executing together to make the system function as as one single entity. So, going back we have in this local network as you are saying then we have the internet, we have the backend services and finally, the applications that I have been served. (Refer Slide Time: 07:20) So, these are the different basic components of IoT. So, this is the scenario that I was referring to earlier. So, what we have we are these different things. These things could be like you know different physical objects which are fitted with different sensors. These things could be telephones, lightning systems, could be cameras, could be different other scanner, sensors like the temperature sensor and so on and these things are able to communicate with one another with the help of wireless technologies like Zigbee, Bluetooth, WiFi and so on. So, as you can see that this wireless basically helps these different devices to talk to one another and this information from these devices, they will go through a local network and from a local network, they will go through the internet to 78 you know these data are basically sent to the backend services involving different servers processors and so on and so forth. For running different analytics and then based on that different devices can be actuated you know may be a pump. This is an example that I gave earlier in a previous lecture basically for agricultural purposes. The use of IoT pump might be started might be actuated based on the data that is received from the sensor nodes and based on analytics are run at the different servers that are involved in the backend service processing. (Refer Slide Time: 09:03) So, in terms of the functional components of IoT, one of the very important things is basically interaction. Interaction not only with the physical environment by this different sensors but also interaction and communication with the different devices, that means, a different nodes in the IoT in the IoT network, then comes the processing. So, processing and analysis of the different functioning and the operations that taken place, so processing of that data, the processing of operations, so this is another component, the third functional component is basically the interaction typically with the internet and because you know at present most of the times, the most of the IoT implementations are still using the internet. So, it is all you know internet powered IoT implementations. So, internet interaction is one of the very important components of building IoT. Then, we have the web services, web services machine to machine communication and so on. So, basically what is going to happen earlier most, when you talk about a web 79 technology, typically we are talking about human to machine communication, you know web service we are talking about you know some machine sending or some equipment basically sensing and sending that data to another machine for further processing or machine to machine communication is involved and offering different services. So, one machine offer some services to another machine and so on. So, this is basically you know this sort of thing in a IoT scenario is taken care of typically and then, we have the integration of different applications services and the user interface to access the IoT. That is another component. So, there has to be a user interface, a human interface to access the IoT network or the IoT you know mega network. (Refer Slide Time: 11:17) So, looking at this particular figure, I would like to try to clarify how the IoT implementation is typically done and it can be done to achieve different application needs. So, this is a figure which shows that we have different sensors, processors and radio. It refitted to each of these devices or the sensor nodes or the sensor motes or the IoT motes as you may want to call them. So, these motes, they talk to one another, but these different sensor nodes, they are basically within the jurisdiction or the domain of the gateway. So, the gateway is basically tasked to assign different locally unique addresses to these different nodes, to these different IoT nodes and the gateway basically takes care of the local addressing within that particular local area network. So, from the 80 that point, all the data can flow through a proxy server if internet access is required. So, it will go through the internet, then a web socket and from the web socket, it goes through a cloud server. That means, this is where lot of analytics and backend processing takes place and based on that the actuation based on the analytics and the infer ant says that and run from the sensed data actuation of different devices can take place. (Refer Slide Time: 12:56). For example, lighting a particular lamp could be the actuation of that particular lamp. We have different interdependencies that are evolved in the implementation of IoT. So, if we look at IoT from another prospective or we have sensors, we have actuators and a bunch of other things that they are in between as shown in this particular figure. So, this is basically the entire spend of these different embedded devices. So, the sensors basically sense the data and that data is basically serving the application requirements and then, we have an operating system and a power management unit which basically you know does things like duty cycling of the sensors, how much the sensors you know how much time we are going to be active or how much time they are going to be in the sleep state, how to power them because these are very small sized you know, very resource staved sensors. So, basically the power unit in these sensor nodes, these are very small in size. So, basically consequently what happens is these embedded devices, they themselves are very resource staved. 81 So, we have a very power management unit which basically takes care of power management as a whole. How much power is required, for how long it is going to power, then what are the ways to harvest energy if at all it can be harvested and how much power consumption is going to take place at different points of time, can it be optimized different points of operation on and so on and so forth and as you can see over here, there after we have these different radios involving bluetooth, Zigbee, 6Low Pan, Wifi, Ethernet and low range basically wifi. So, these are the different you know radios that can help in communicating the data that is sensed onward to other nodes. These basically different radio technologies can help for the communication purpose. So, alongside we also have things like virtual machines which takes care of the virtualization of the nodes, we have the web, we have you know different things like http client MQTT client, CoAP client. So, these are the once MQTT CoAP, we are going to talk next in the subsequent lectures. So, that will make our understanding clear, but these are like no different application level protocols that are used for functioning of these different IoT devices and finally comes the actuator verticals. So, we have the sensors, we have different applications operating system, power management, radios, virtual machines web and then, we have these actuators all together which forms the embedded systems, the embedded devices. (Refer Slide Time: 16:09). 82 Now, let us look at the service orientation, the service oriented architecture of IoT. So, in the IoT if here what we have at these different layers, the sensing layer, the network layer, the service layer and the interface layer. So, we have four different layers and as the name suggests, sensing layer basically takes care of sensing through different RFIF tags sensors and so on and so forth and then, data are sensed are acquired and so on are sent to the next layer higher up which is the network layer. The network layer basically serves sensor networks, social networks you know different other networks and data bases internet and so on. That is the network layer. Then, what we have? We have the service layer which deals mostly with the service delivery such as service, division service, integration service, repository service, logic by business logic and so on. So, all these different things that I involved with the offering of the services to support the business functions. Then, we have the interface layer, we have the application frontend, we have a contract interface and application APIS. So, this becomes the interface layer and when we have the security issues which basically span all these different layer verticals, sorry layer horizontals. (Refer Slide Time: 17:50). So, in terms of the categorization of IoT, it can be categorized into two. One is the consumer IoT which is what typically most of the people tempt to use and these are here, basically these different devices, they communicate with another through these local 83 networks and it can be you know find a further communication can also take place over the internet as well depending on the requirements either local or through the internet. Then, we have the local communication which is typically done via bluetooth, zigbee or wifi. So, basically this local communication is constraint within the bounds or within the domain of the IoT gateway. So, this is consumer IoT. Then, we have the industrial IoT which is basically quite similar to the consumer IoT, but the application interest is in the industrial sector. So, we are talking about manufacturing industries with different machines, with these machines are fitted with different IoT devices and they together become the IoT device. They have different sensors and so on feature are there which can node as a whole can communicate with other machines and so on. So, this becomes the industrial IoT and basically, there are different communication that takes place between the different nodes as well as different industry specific technologies. Now, we talk about IoT gateways. (Refer Slide Time: 19:25). So, this is what I told you that in a local network, you have this loca