 Welcome, Myself, Mr. Vishal Angeere, Assistant Professor, Department of Electronics and Telecommunication, Vulture Institute of Technology. Today, we are going to study communication technology used for IoT and that is ZigBee. Learning outcome, at the end of this session, students will be able to explain ZigBee module. So, before starting with ZigBee technology, students should know what is wireless sensor network. Now, we will start with what is ZigBee technology? ZigBee communication technology is specifically used for controlling and wireless sensor networks on IEEE 802.15.4 standard for wireless personal area network and it is the product from ZigBee alliances. So, ZigBee module is basically used for controlling of the devices as well as for wireless sensor networks. ZigBee module works on the frequency of 868 MHz, 928 MHz and 2.4 GHz. Now, we will see ZigBee architecture, so the figure shown, ZigBee system structure, so generally there is two type of connections, one is wired connection and another is wireless connection. So, there is one existing network with that one ZigBee coordinator is to be connected and that ZigBee coordinator is connected with ZigBee routers as well as ZigBee end devices. So, in this example of ZigBee system structure, you can see existing network is connected with one ZigBee coordinator which will act as a master and that master is to be connected with ZigBee routers, so that routers can transmit or receive data to or from a slave to master or from master to slave and ZigBee which is to be used at end devices. Now, we will see ZigBee architecture, so in this ZigBee architecture, it will have ZigBee protocols and it is less, so generally there are five layers, first one is physical layer, second one is MAC layer which is also called as a media access layer, next one is network layer and after that application support sub layer and after that application framework. So, generally physical layer is to be used for modulation as well as demodulation while transmitting or receiving the data. Next media access layer is to be used for sending or receiving the data packets or data frames. Network layer is to be used to handle network related issues like configuring the devices, setting the network between master as well as slave. Next application support sub layer is to be used to handle issues related to ZigBee device object and application object and next is application framework, so that application framework will consist of application object 240, application object 1 and ZigBee device object. So, the security service provided in this ZigBee architecture by network layer as well as application support sub layer, now we will see ZigBee operating modes and its topologies, so the diagram is of ZigBee communication operation, so ZigBee will operate in two different modes, one is back on mode and second one is non-back on mode. In back on mode coordinator as well as router are active and they will continuously monitor the data which is transmitted or received, so in this type of communication mode of ZigBee there is a power consumption or energy is required more and in the second mode that is non-back on mode the coordinator as well as router will go into sleep mode and when it is required to send or receive data at that time only the coordinator as well as router are to be activated, so power consumption is less in this second mode of communication. Now we will see ZigBee topologies, so three different type of topologies are to be used that is network topologies, one is star topology, second one is mesh topology and third one is cluster tree, in star topology there is one ZigBee coordinator and number of ZigBee devices, so devices will have one ZigBee module and those devices are to be connected to one ZigBee coordinator, so in star topology all the devices can contact or are to be connected to ZigBee coordinator, so such type of star topology is to be used in industries in which all the end devices can directly connect to ZigBee coordinator. Next is mesh topology, so in mesh topology there is one ZigBee coordinator, number of routers as well as number of ZigBee devices, so each device will have a ZigBee module and there are number of routers as well as one ZigBee coordinator which will act as a master and there are number of slaves, so in this type of topology all the ZigBee devices can communicate with each other because of the routers and mesh topology is to be generally used in wireless sensor network because if any one ZigBee device is damaged in that case data is to be transferred to another ZigBee device, so like that there will not be any loss of data. Next one is cluster tree, so you can see that there is one ZigBee coordinator and that ZigBee coordinator is connected to ZigBee router and ZigBee router is to be connected to many ZigBee devices, so the structure is like cluster tree, so these are the three different ZigBee topologies, first one is star, second one is mesh and third one is cluster tree. Now we will see application of ZigBee technology, first one is home automation, so in case of home automation number of devices are to be connected to ZigBee and those devices are to be controlled, as an example you can control tubes, bulbs as well as fans which are present in home with the help of ZigBee you can control these appliances or devices you can turn on and turn off fans regulators with the help of ZigBee module. Second application is industrial automation, so in industries there is a requirement of monitoring the process which is going on in the factories or industries, so for the monitoring of those machines which are present in industry a ZigBee modules are to be used. Next application is smart grid monitoring, so in smart grid monitoring the temperature is to be monitored continuously with the help of ZigBee modules. Last application is smart metering, so in smart metering the energy is to be calculated or monitored continuously with the help of ZigBee module as well as energy theft is to be monitored with the help of ZigBee module, so in case of smart metering energy calculations as well as energy theft is to be monitored with the help of ZigBee modules. So the ZigBee modules are very much useful in wireless sensor network as well as controlling of the devices and ZigBee modules are very much effective low cost and it requires very much low power, so ZigBee modules are efficient as compared to its other competitors like Bluetooth, Wi-Fi, RFID as well as NFC. While preparing this video lecture I have used internet of things architecture and design principles by Raj Kamal, Internet of Things for Architects by Peri Lee. Thank you.