【IoT Graduation Project】Research on Gizwits AIoT+WiFi Technology+Intelligent Control System of Teaching Building
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Abstract: Aiming at the current situation that most of the equipment in teaching buildings is controlled individually and manually, and people have higher and higher requirements for the safety and comfort of the teaching environment, an intelligent control system for teaching building equipment is designed. The system uses a single-chip microcomputer as the control core, combined with sensor technology, WiFi technology and Gizwits cloud technology for comprehensive control, improves the intelligent control of equipment, reduces power loss, increases the safety of teaching buildings, and ensures the safety of teachers and students as well as teaching equipment. The system has the characteristics of simple operation, low price, stable system and high sensitivity. At the same time, it can also perform remote monitoring, and has good application prospects in public buildings. 0Introduction
With the continuous improvement of science and technology and economic level in my country, people's material needs are also increasing, and the requirements for comfort and convenience of study and life are also increasing. In schools, the most frequently used buildings are the teaching buildings besides dormitories, so this project changes the equipment control of the teaching buildings. Based on this background, this project takes the teaching building as the design site, and uses the single-chip microcomputer as the core to design an intelligent, energy-saving and safe teaching building intelligent control system through the cooperation of sensors and Wi-Fi modules to solve the problems of comfort, controllability and safety of the teaching building.
1 System Design Overview
In order to realize the intelligent control of the teaching building, this design takes the single-chip microcomputer chip as the core to control other functional modules. The functional modules include: display module, lighting control module, clock module, temperature and humidity acquisition module, communication module, human infrared sensing module and smoke sensor [1]. The control execution output part uses a 4-phase 5-wire stepper motor, a servo, a relay, a humidifier and a heating plate. The signal prompt part uses a buzzer and a decibel alarm. This system uses KEIL5 as the development software and uses a modular design. The main program module is the main idea and logic of the entire circuit operation. USB is used to power the system and burn the program. The overall structure of the system is shown in Figure 1.
Figure 1 Overall structure of the system
2 System Hardware Design
2.1 Microprocessor Module
The minimum system of the single-chip microcomputer is mainly composed of a clock circuit, a reset circuit, a power supply circuit and an STC89C52RC chip. It has the advantages of strong control function, flexible expansion, miniaturization and ease of use, meeting the design requirements [2]. The STM32 F103C8T6 single-chip microcomputer with richer peripherals can be widely used in different scenarios by taking advantage of its high performance, low cost and low power consumption. 2.2 Hardware design for time synchronization and ringing bell
The time-setting bell system uses LCD to display real-time time and set get out of class start and end times. When the class start and end time are consistent with the chip time, teachers and students are informed of the start and end of classes.
2.2.1 Clock and bell module
The real-time clock module is composed of a DS1302 chip and a backup battery CR2032. The real-time clock calculates the system based on the set initial time and provides the system with information on year, month, day, hour, minute, second, and week. It adjusts the number of days per month through its built-in leap year compensation function [3]. It has the advantages of accurate timing, simple interface, easy use, and a wide operating voltage range. The reminder module composed of a buzzer is used in conjunction with the timed bell of the teaching building.
2.2.2 Display and setting module
The classification trash can system classifies metal trash and wet trash. When the trash and the corresponding category are sensed at the same time, the trash can will open automatically.
2.3.1SG90 Servo and Infrared Module
The JS01 metal sensor generates an induction current when a metal object approaches, thereby outputting a high level to the microcontroller to achieve the goal of metal detection. Its sensitivity can also be changed by adjusting the potentiometer. The humidity sensor detects the humidity of the environment by comparing it with the set threshold. When the actual value is greater than the set value, it outputs a low level to detect wet garbage [4]. By using the metal sensor and the humidity sensor together, classified garbage bins can be used in teaching buildings.
2.4 Security Alarm Hardware Design
The security alarm system is set in the classroom during class breaks. If the human body sensing module senses someone, it will send out an alarm signal to prevent theft. The smoke alarm module is: when a fire occurs, the smoke concentration is too high and the smoke alarm will be activated. The smoke alarm sends out an alarm signal to help teachers and students stay away from danger.
2.4.11HC-SR501 Human Body Sensor Module
The HC-SR501 human body sensing module has the characteristics of fully automatic sensing. When the device is started and a human body is detected within the sensing range, it will output a high level to the microcontroller and cooperate with the alarm to realize the anti-theft function and ensure the property safety of the teaching building [5].
2.5 Student Attendance Hardware Design
The student attendance system records the attendance of students when they enter the classroom, and uploads the attendance data to the cloud platform, which can be monitored in real time on the user side.
2.5.2RC522-IC card sensing module and OLED display
RC522 is a member of a series of highly integrated card reader/writer chips for 13.56MHz contactless communication. It is a low-voltage, low-cost, small contactless card reader/writer chip launched by NXP for "three-meter" applications [6]. If an IC card approaches, the RFID reader module reads the ID in the IC card and sends it to the microcontroller module through the serial port. Compared with the crystal layer of LED or LCD, the organic plastic layer of 0.96-inch OLED liquid crystal is thinner, lighter and more flexible, and it is self-luminous and consumes less energy. The microcontroller module receives the ID in the IC card and compares it with the ID stored in the FLASH. If the comparison is successful, the student's attendance card is successfully punched in and the student's student number and name are displayed on the OLED.
2.6 Temperature and humidity measurement and control hardware design
Temperature and humidity measurement and control is to meet people's comfort requirements by collecting the temperature and humidity of the surrounding environment and adjusting the appropriate temperature and humidity range. The DHT11 temperature and humidity sensor collects the temperature and humidity in the environment in real time, and then transmits the digital signal to the single-chip microcomputer, which is displayed on the LCD12864 liquid crystal screen. At the same time, the real-time parameters are compared with the set thresholds to control the operation of related equipment, ensure the comfort level of indoor temperature and humidity, and reduce power loss [7]. The advantages of the DHT11 digital temperature and humidity sensor, such as ultra-fast response, strong anti-interference ability, and long-distance signal transmission, are used to ensure the stability and accuracy of temperature and humidity detection.
3. System software design
3.1 Design of time-setting and bell-ringing software
The time-setting and bell-ringing system first reads data from the real-time chip DS1302, then initializes the LCD display, and displays the real-time time on the LCD screen through the DS1302 chip. The bell-ringing time for get out of class start and end can also be set and the real-time time can be calibrated through independent buttons to improve accuracy [8]. When the actual time is the same as the set class start and end time, the buzzer will ring. The software flow chart of the time-setting and bell-ringing system is shown in Figure 2.
Figure 2: Software flow chart for time-setting and bell-ringing
3.2 Classification Trash Can Software Design
After initialization, when the infrared sensor senses someone, the metal garbage bin will automatically open when metal garbage is detected, and will automatically close when it detects no one after a delay. When wet garbage is detected, the wet garbage bin will open, and will automatically close when it senses no one after a delay.
The software flow chart of the classified trash can is shown in Figure 3.
Figure 3 Flowchart of Classified Trash Can Software
3.3 Security alarm software design
First, after the blocks are initialized and the defense mode is set, the alarm is triggered when someone is sensed. The smoke sensor continuously outputs analog voltage to the microcontroller. When the smoke concentration reaches the safety value set by the microcontroller, the alarm sounds.
3.4 Student Attendance Software Design
After the modules are initialized, it is determined whether the MFRC522 module has successfully read the IC card number. If the card is punched successfully, the count is increased by 1, and the student's corresponding student number is displayed on the OLED. The counting result is connected to Gizwits Cloud using a single-chip microcomputer and esp8266-01S , and the counting result is uploaded to the Gizwits Cloud App. The student attendance can be remotely monitored on the Gizwits Cloud platform. 3.5 Design of temperature and humidity measurement and control module
The DHT11 temperature and humidity module collects and processes the indoor temperature and humidity data, and then transmits it to the single-chip microcomputer for data reading and processing. After the single-chip microcomputer processes and analyzes it, it outputs the data signal to the execution output relay module LCD12864 display program module [9-10]. At the same time, the system will also compare the collected real-time data with the set relevant thresholds. If the temperature and humidity exceed the upper limit, the fan will start; if the temperature and humidity are lower than the lower limit, the heating plate humidifier will start. The main program module will continue to cycle according to the design function of the system, thereby realizing the operation of the entire system. The software design flow chart of temperature and humidity measurement and control is shown in Figure 4.
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Figure 4: Software design flow chart for temperature and humidity measurement and control
3.6 Function and Implementation
The main controller is connected to the mobile device through the Wi-Fi module, and the student attendance is remotely monitored through the Gizwits Cloud App. Various sensors in the teaching building collect data about the surrounding environment and display it on the LCD screen. When the data collected by the sensor changes or exceeds the standard, some startup work is performed, and the electrical signal output by the sensor and the data result are used to determine whether to issue an alarm [11].
4 Conclusion
In order to meet the high demand of modern people for the comfort of teaching building environment, this paper designs a teaching building system that can automatically control the teaching building system as the surrounding environment changes. It has the characteristics of convenience, environmental protection and safety. It combines intelligent control with environmental protection and energy saving, which is more in line with the general direction of modern scientific and technological development.
The traditional teaching building environment adjustment is only manual, which is cumbersome and cannot accurately and timely sense the surrounding temperature. Therefore, this design adds a single-chip microcomputer to control the teaching building system environment to ensure the stability and reliability of the circuit, and has the characteristics of complete control functions, low power consumption, low cost, high degree of automation, simple principle and program design, etc. It is a more effective and convenient method. However, the disadvantage is that it only designs some basic functions and cannot meet the needs of all users. With the rapid development of intelligence in the future, its functions need to be enhanced.
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提升卡
变色卡
千斤顶
