A new multi-functional smart home controller is designed with Arduino module as the core.
The controller chooses LD3320 module for voice acquisition, recognition and alarm, WIFI module and Zigbee module for wireless communication and control of signals, and HR911105A interface module for intelligent control of network, so as to realize remote intelligent control of household equipment without geographical, multi-mode and intellectualized. With the continuous progress of science and technology and the continuous improvement of the quality of life requirements, people in the choice and use of household appliances, has changed from a single function of traditional household appliances to intelligent household appliances. Smart home controller can provide a variety of home appliances intelligent control schemes, so that home owners can enjoy family life more, and enable them to handle family affairs faster, more convenient, and provide them with more suitable living space.
However, the market of smart home is complex, and it is difficult for existing smart home systems to achieve real intelligence.
In addition, the diversity of smart devices, the compatibility of smart systems, the high price and many other factors make it difficult for smart home to truly enter the public life. According to the needs of modern life for convenience, safety and comfort of living environment, thermostatic element this paper designs a new type of multi-functional intelligent home controller, which realizes the wireless transmission and remote control of household appliances with low power consumption, high reliability, scalability and flexibility. As shown in Fig. 1, the overall scheme of smart home controller is composed of main controller, wireless transmission module, speech recognition module, network interface module and wireless transmitting/receiving module. The main controller adopts Arduino MCU module with high cost performance; speech recognition module is responsible for voice command acquisition, recognition and voice alarm; network interface module is responsible for network communication between mobile terminal and main controller; wireless transmission module is responsible for receiving real-time monitoring signals of indoor temperature and humidity, combustible gas sensors, and on.
The wireless transmitting module is responsible for transmitting the home appliance control commands issued by the main controller, while the wireless receiving module receives the commands and transmits them to the execution module. The main controller module Arduino Mega2560 is the latest easy-to-use open source controller introduced by Atmel Company in 2013. It is based on ATmega2560-16AU microcontroller. The main controller module circuit mainly includes the minimum system of single chip computer and download program interface. The minimum system of single-chip computer includes single-chip computer, power supply circuit and reset circuit. ATmega2560-16AU MCU has abundant resources, high cost performance, 16MHz crystal oscillator, processing speed up to 20MIPS, and has 54 I/O ports, 256KB Flash Memory, 8KB SRAM, 4KB EEPROM, and 4 UART interfaces.
The main controller module can automatically select power supply mode through three ways (external DC power supply, battery power supply and USB interface power supply), and provide automatic reset design, which can be automatically reset through Arduino software download program.
The MCU on the main controller module has preset bootloader program, which can be downloaded directly through ICSP header on the MCU. The speech recognition module of the system adopts the high performance LD3320 speech recognition chip of ICRoute Company. It integrates speech recognition processor and external circuit, and can capture, recognize, process and broadcast speech signals.
LD3320 chip has 16 bits A/D converter, 16 bits D/A converter and power amplifier circuit. It does not need any auxiliary Flash chip, RAM chip and A/D chip. It can directly realize speech recognition, voice control and human-computer dialogue functions.
The types of recognition include words, phrases and so on.
The speech recognition rate is relatively stable and the accuracy rate is relatively high. The interface mode between speech recognition module and MCU is parallel, and its control signal and interrupt return signal are directly connected with MCU. The working principle of speech recognition is as follows: firstly, the input sound is analyzed by spectrum, then the speech feature information is extracted, finally, the data in the training template is matched with the feature information, and the recognition result is output. In this system, 315M wireless module is used to complete the communication between MCU and equipment. The signal is collected, transmitted, received and transmitted by 315M wireless module. M wireless module is divided into data transmitting module and receiving module. The data transmission module has a wider working voltage, the optimum working voltage is 12V, which can be transmitted up to 500 meters. ASK modulation can prolong the service life. The transmission distance varies with the field environment, mainly affected by modulation signal, transmission voltage, receiver sensitivity and other factors.
To a certain extent, the receiving module is only a component, which is effective only when combined with the transmitting circuit and single chip computer. Receiving module can infiltrate flexibly in circuit design to reduce interference and ensure signal stability. In this design system, ZigBee wireless transmission module is used to “interact” information between smoke, temperature and humidity sensors and Arduino modules. Zigbee is a short-distance, low-rate wireless networking technology. In ZigBee network, the communication between devices is stable, without artificial settings, and the anti-jamming ability is strong. Zigbee module provides SMT and DIP interface, which can directly connect TTL interface equipment, realize data transparent transmission function and long communication distance. The biggest bright spot is that ZigBee technology can be self-organized. Through dynamic routing and network topology, the data can be transmitted to the destination stably. Software design is based on Code Composer Studio IDE integrated development environment and Keil C51 language.
Software modules mainly include: main function, voice alarm sub-function, network interface sub-function, wireless transmission sub-function and wireless transceiver sub-function. Speech recognition and broadcasting are carried out by speech recognition module LD3320. The analog signal is converted into digital signal through Arduino module to 315 transmission module. Then the relay receives the analog signal and makes the specified “action”, as shown in Figure 2. The smoke sensor collects information, transmits the signal to Arduino through ZigBee module, and then converts the signal into a digital signal recognized by LD3320 module to complete voice alarm, as shown in Figure 3. The signal of mobile phone/PC is sent to HR911105 module through cloud, and then Arduino captures the signal and converts it into digital signal and transmits it to voice module to complete the alarm work, as shown in Figure 4. This project combines the new Internet of Things technology and the existing multimedia information technology means, designs a new type of multi-functional smart home controller, which can control household appliances by wireless remote control through voice, mobile phone, PC equipment and mobile network, and realizes integrated control in many ways. At the same time, it also has the functions of home fire monitoring and voice network alarm, which truly reflects the connotation of smart home and makes the communication between household appliances and our human beings simpler, faster and more efficient.