From smart bracelets, smart watches, VR, AR, MR, shared bicycles to driverless, the Internet of Things will completely subvert our lives, just reading a book on "Illustration of Internet of Things", which uses graphic text. The way to make a very thorough interpretation of the Internet of Things and related technologies, hereby share with you.
    First, understand the Internet of Things Internet of Things Internet is Things, abbreviated as IoT, here "object" refers to everything around us that can be connected to the network, not everything, but specifically refers to things that can connect to the Internet, If clothes, watches, and shoes can connect to the Internet, it is what IoT refers to. If it is just cockroaches, dirt, air, toilet paper, or even the keyboard I am typing (ordinary keyboard), it is not an object in the Internet of Things.
    With the spread of broadband, ultra-low-power sensors that can be installed on machines have entered the market, and advances in wireless communications have prompted more and more kinds of traditional Internet-connected devices such as PCs, servers, and smart phones. Various "things" have also begun to connect with the Internet of Things, starting with cars, household appliances and houses. In recent years, watches, eyes and other accessories have also been connected to the Internet.
     We must know why there are so many devices that have the demand for networking. What value do they bring to users when they go online?
    In the past, people realized the remote control of “things” by letting a few expensive industrial machinery communicate (that is, the control systems commonly used in the discrete/process industry). In the future, people will be more productive at a lower price. The user's machines, and let these machines communicate, are also due to the application of the data obtained from these "things", a variety of services have sprung up.
    In addition, the popularization of advanced sensing technology has enabled human beings to grasp and predict the real world. It is also expected to build new social infrastructure by collecting human, material, social and environmental data in real time.
    The following is a smart home case that automatically controls the environment based on human conditions.

How to understand the Internet of Things

The following is a floor environment monitoring system that enhances the comfort of an office-based workplace environment.

How to understand the Internet of Things

Second, the technical architecture of the Internet of Things When the Internet of Things is realized, the Internet of Things service plays a two-fold role. The first is to save the data received by the device to the database and analyze the collected data. The second is to send instructions and information to the device. The Internet of Things is generally composed of devices, networks, gateways, servers, etc., as shown in the following figure, which will be introduced separately below.

How to understand the Internet of Things

Third, equipment - the interface to the real world IoT equipment is varied, when its structure is generally as shown below. IoT devices, like ordinary mechanical products, contain input devices for detecting user operations and changes in the surrounding environment of the device, prompting certain information or output devices that directly act on the environment, and acting as the brain of the device to control the micro-machine. Controller, etc.

How to understand the Internet of Things

1. The microcontroller MCU is an IC chip that controls the machine. It can write programs and read IO states according to the described processing, or output specific signals to the connected circuits. The difference from the chip in the PC is that it is usually more integrated and will include both CPU, memory and peripheral circuits, as shown in the following figure:

How to understand the Internet of Things

Most electronic products are now equipped with microcontrollers. In recent years, the cost of 32-bit microcontrollers has gradually decreased, and they have begun to replace the traditional 8-bit microcontrollers. In particular, it is now necessary to connect devices to the network, and to control micro-controllers. The motherboard and programming environment requirements are also gradually reduced. Many developers who have never touched the hardware can easily make many IoT products by connecting some standard peripheral I/O devices. For example, the Arduino motherboard is a microcontroller motherboard that can be developed by anyone who has not been engaged in the design and production of electronic instruments. It has a high popularity, utilizes its IDE development environment, and a large number of scalable Shields. It takes dozens of blocks to build a gadget for connecting to the Internet of Things.

How to understand the Internet of Things

When it comes to open source hardware, there is one more to mention. That is the famous Raspberry Pi, which is equipped with a high-performance ARM processor, can directly run the Linux operating system, and is equipped with a wealth of peripherals, USB, HDMI, live off is the rhythm of a mini PC, the price must be More expensive than Ardunio, but recently there are many cottage development boards in China, what banana pie, orange pie, similar functions, lower cost, very suitable for newcomers to learn.

How to understand the Internet of Things

In order to attack ARM's expansion in the field of Internet of Things, Intel is not outdone. It has launched an Edision development board specifically for the Internet of Things. It integrates multiple protocols such as WiFi and Bluetooth 4.0. It is also compatible with Ardunio extensions, installing Python and Node.js and dedicated. XDK IoT Edison Development Kit.

How to understand the Internet of Things

2. Input devices In order for the device to obtain information such as surrounding conditions and user operations, components such as sensors and buttons (electronic devices) must be implemented on the machine. For example, suppose there is a smart phone, then what kind of sensor is equipped with this mobile phone? In fact, it is equipped with a large number of sensing devices such as touch screen, buttons, cameras, accelerometers, and camera sensors. Sensing equipment can help us master the surrounding situation in more detail and fineness, which determines the performance of the machine to a certain extent. Therefore, the selection of sensors is a very important step in the development of the equipment. The following table shows the representative sensors. :

How to understand the Internet of Things

How to understand the Internet of Things

The table below shows typical sensors and featured sensors for wearable devices:

How to understand the Internet of Things

How to understand the Internet of Things

Each sensor has different detection elements built in according to its purpose. The electronic characteristics of the substance of the detection element vary according to the surrounding environment, as shown in the following figure:

How to understand the Internet of Things

With the miniaturization of parts and the emergence of high-performance small processors, there are sensors with advanced capabilities on the market that can easily capture information that was previously difficult to process as data. These sensors are not so much a part. It is a device in a narrow sense, or a system with multiple factors and complex cooperation. For example, the RGB-D sensor is actually an enhanced version of the camera. It can not only take pictures, but also measure the distance from the sensor to the object. The realization principle is to use the difference between the two images to measure the distance in the captured image. The imitation is also the principle of human eyes ranging (otherwise we can only see two-dimensional things), this technology has been relatively mature, in recent years, the auxiliary functions equipped on the car (such as automatic deceleration, fast deceleration, etc.) also applied similar The principle.

How to understand the Internet of Things

How to understand the Internet of Things

For example, positioning is also crucial for the Internet of Things. Whether it is to navigate through navigation, to monitor the water storage capacity of dams, or to protect endangered species, or to optimize transportation routes, and to monitor tsunami on the ocean, positioning technology is now not only There are GPS, WIFI positioning, fingerprint positioning and so on. 3, the output device IoT wants to achieve not only the sensing state, the state "visualization", interference with humans and the environment, control the world to make it to the target state is its real purpose. When it is necessary to feed back some information to the user, devices such as monitors, speakers, and LEDs that output information will function. IoT devices are small and simple. How to configure these output devices allows them to efficiently communicate information to Users are undoubtedly a very important topic in the design phase. Another method is to install a driver on the device, so that the driver physically acts on the environment. The driver is a general term for the drive device that controls the input signal, such as a representative servo motor, which can drive the motor according to the input electronic signal. Rotating to any angle, this method is closely related to robot technology, and the equipment linked to the network is one of the most attractive areas today. Fourth, the network and the gateway have two ways to connect to the network, one is directly connected to the global network by the device itself, and the other is to use the gateway to connect to the global network in the local area, as shown in the following figure, the recent "life record" More and more types of devices, the structure is closer to the second way mentioned above, such as pairing the wearable device with the smart phone via Bluetooth, sending data to the server through the smart phone.

How to understand the Internet of Things

1. There are many ways for network IoT devices and gateway devices to communicate. There are both wired and wireless. Each method has its own advantages and disadvantages. Wired includes Ethernet, serial communication (generally RS-232C), USB. Etc., wireless includes WIFI, Bluetooth, 2G/3G/4G, and of course NB-IoT. For example, the shared bicycle is actually purchased from the operator's SIM card. The network specifications of the three major operators are as follows:

How to understand the Internet of Things

So what is NB-IoT? From 2G to 3G to 4G, the mobile network speed is getting faster and faster, but after the 4G era, due to the emergence of the Internet of Things, the development of mobile communication networks has branches:

How to understand the Internet of Things

It can be seen that one side is large traffic, one side is small data, one side is mobile broadband, and the other is the Internet of Things era. From 2G to 4G, mobile communication networks are only born to connect with "people", but with the era of all things connected In the coming, the mobile communication network needs to evolve toward the connection "things". To this end, 3GPP has developed the NB-IoT standard in Release 13 to cope with the current demand for Internet of Things. In the terminal support, there is also a terminal level corresponding to NB-IoT-cat-NB1, which is more traditional 2/3/. 4G network, the Internet of Things has three main characteristics: First: lazy, the terminal is very lazy, most of the time sleeping, the amount of data transmitted every day is extremely low, and allows a certain transmission delay (for example, smart water meter). Second: Static, not all terminals need mobility, and a large number of IoT terminals are in a static state for a long time. Third: the uplink is the main, and the connection with the "person" is different. The traffic model of the Internet of Things is no longer the following behavioral master, and may be the main behavior.

How to understand the Internet of Things

These three features support the "compromise" of technology at low rates and transmission delays, enabling coverage-enhanced, low-power, low-cost cellular Internet of Things. NB-IoT has become the most trusted IoT communication technology for operators. The core technology of operators implementing the Internet of Things strategy. 2. Gateway Gateway refers to a machine and software that can connect multiple devices and have the function of directly connecting to the Internet. It converts the data received from the device into a specific format and sends it to the server, as shown in the following figure. Of the devices used, three devices cannot be directly connected to the Internet, and the gateway is responsible for forwarding these devices to the Internet.

How to understand the Internet of Things

How to understand the Internet of Things

V. The server IoT service can be roughly divided into three parts, which are called the front part, the processing part and the database part.

How to understand the Internet of Things

1. The receiving data data receiving server is responsible for receiving the data sent from the device. It plays a bridge between the device and the system. Generally, the protocols used include http, WebSocket, etc., and another is the MQTT new protocol, and the Internet of Things field will It is a standard protocol, which is a protocol that enables one-to-many communication (known as publishing or subscription). It consists of three functions, namely mediation, publisher, and subscriber, as shown in the following figure:

How to understand the Internet of Things

Like this, through the intermediary of publish/subscribe communication, MQTT can realize the communication between the Internet of Things service and multiple devices. In addition, MQTT also implements a lightweight protocol, so it can also have low network bandwidth and reliability. It runs under low-environment environment, and because the message is small and the protocol mechanism is simple, it can also run under the condition of limited hardware resources. It can be said that it is a protocol tailored for the Internet of Things. 2, the data format data to be exchanged through the protocol, and the format of the data is also very important, the data format used by the Web protocol, including XML and JSON, as shown below:

How to understand the Internet of Things

Relatively speaking, XML is easy to understand, and JSON has few characters and small amount of data. It is more suitable for low-speed line communication such as mobile lines. When these formats are processed based on IoT services, text data is converted into numerical data and binary data. In order to process the data more quickly, a new data format is created, which is the MessagePack. Although it is not convenient for people to read directly, the computer is easy to handle. 3, processing and storage data processing server is the place to process the received data, here can be summarized into the following four: data analysis, data processing, data storage and instructions to the device, as shown below:

How to understand the Internet of Things

Data processing includes batch processing and stream processing. The data storage includes relational database and NoSQL database. For details, refer to the mainstream technologies of current big data platforms, such as batch processing with Hadoop MR, Spark, etc., stream processing with Spark Stream, Storm, etc., NoSQL. The database includes KV databases (such as Redis), document databases (such as MongoDB), and so on. 4. The purpose of sending the data sending server is to send data to the device and control the device. The sending server can adopt the HTTP, WebSocket, MQTT protocol and data format introduced above. The following is an example of sending data using the MQTT protocol:

How to understand the Internet of Things

First, the device acts as a subscriber, subscribes to the MQTT broker, and then the sender server is the publisher, which also publishes to the broker. In this way, the sending server only needs to add the determined data to the topic and send it to the server. Devices do not need to know each other's addresses. As long as they know the address of the intermediary, they can communicate. Once the subscriber is disconnected, the intermediary will be responsible for sending notifications when disconnected and sending data again when reconnecting. Here is an example. In recent years, ICT technology has been popularized in the agricultural field. In the past, environmental control was carried out by farmers to manually measure problems in the greenhouse and control the growth of plants.
点击图标下载 App