The Origin and Development of Building Automation and Intelligent Buildings
Building Automation Systems (BAS) are a key component of intelligent buildings. Intelligent buildings utilize BAS to achieve comprehensive monitoring and management of equipment and the building environment within a building (or group of buildings), creating a comfortable, safe, economical, efficient, and convenient working and living environment for users. Furthermore, by optimizing equipment operation and management, operating costs are reduced. BAS encompasses equipment and systems related to power, lighting, air conditioning, ventilation, water supply and drainage, disaster prevention, security, and parking management. It is the most comprehensive subsystem within an intelligent building, involving the largest design tasks and engineering construction volume. Its design level and construction quality directly impact the realization of intelligent building functions.
Early building automation systems typically only included automatic control systems for building equipment. With the development of computer technology, digital communication technology, control technology, and microelectronics technology, automatic control systems for other building equipment have gradually been integrated into building automation systems, such as automatic fire alarm and fire extinguishing equipment control systems, and smart card device control systems. Modern intelligent building automation systems are highly integrated, harmoniously interactive, and possess a unified operating interface—a truly "highly intelligent" automation system.
The rapid development of information technology has fundamentally changed building automation systems. In the past, building automation systems were typically separate from IT systems in smart buildings. However, with the increasing popularity of enterprise-level management and the development of open systems technology and the Internet, simple property management will inevitably be integrated into enterprise management. Automation systems using proprietary communication protocols will be replaced by those using open communication protocols, achieving full interoperability across the entire building automation system. The Internet will become the infrastructure of the management system, forming a networked building system that truly becomes a subsystem of the enterprise-level information system. This networked building system not only provides a unified user interface for building automation systems but also makes enterprise management, including property management, more efficient.
With the progress and development of society and technology, the building environment provided by building automation systems alone can no longer adapt to the rapid development of information technology and meet people's needs for information-based and intelligent building environments. The term "intelligent building" first appeared in promotional materials for the City Place building, completed in Hartford, Connecticut, USA in January 1984, marking the formation of the concept. This building used the most advanced technology at the time to control air conditioning, lighting, fire prevention and security systems, vertical transportation (elevators), communication, and office automation, providing not only a comfortable and safe working environment but also high efficiency and economy. Building users could access various information services such as voice, text, and data, while the building's air conditioning, water supply, fire prevention and security, and power distribution systems were all computer-controlled, achieving automated integrated management and providing users with a comfortable, convenient, and safe building environment, attracting worldwide attention.
Subsequently, intelligent buildings and their "building intelligence systems" flourished, with the United States and Japan being the most prominent examples. In addition, intelligent buildings have also developed rapidly in European countries such as France, Switzerland, and the United Kingdom, as well as in countries and regions such as Singapore, Malaysia, and Hong Kong. According to statistics, the United States has over 10,000 intelligent buildings, and more than 60% of newly constructed buildings in Japan are intelligent buildings. my country's intelligent building industry started relatively late, only achieving significant development in the late 1980s, but its rapid development has attracted worldwide attention. In recent years, a number of intelligent buildings with considerable capabilities have been built in cities such as Beijing, Shanghai, Guangzhou, and Shenzhen, including the Beijing Development Building, the Jin Mao Tower in Shanghai, and the Tianan Digital City in Shenzhen. Currently, intelligent building development in China is beginning to shift towards large public buildings, such as convention centers, libraries, stadiums, and even urban information-based communities.
According to foreign media predictions, large-scale buildings under construction in China in the near future will account for half of the global total, and more than half of the world's smart buildings in the 21st century will be built in China.
Two wireless visual doorbell systems
In my country, smart residential communities are becoming increasingly common. Modern smart residential communities are based on high technology, utilizing advanced equipment and management methods. They employ the latest computer and related technologies, incorporating modern computer, sensor, transmission, network, and automatic control technologies into traditional building structures to improve efficiency, reduce losses, and save costs. This continuously enhances the automation level of property management, security, and information services within residential communities, providing residents with a safe, convenient, and comfortable living space.
Three essential security measures for smart communities:
The first line of defense is a CCTV surveillance system: Advanced active infrared intrusion detectors are installed on the walls and fences surrounding the gated residential complex. These detectors use infrared beams to seal off the perimeter; if someone climbs over the wall, the electronic map at the monitoring center quickly displays the location of the incident and triggers an audible and visual alarm, alerting on-duty personnel to respond promptly. Based on the alarm location displayed on the electronic map, on-duty personnel use a radio to call nearby patrol officers to handle the situation. CCTV systems are also installed at the main gates, parking lot entrances/exits, elevator cars, and main passageways within the residential complex, providing 24-hour monitoring and recording. Personnel at the monitoring center can review the situation at any time via the CCTV footage, providing valuable visual evidence to the police in case of an incident.
The second line of defense is the electronic patrol system: Recording devices for the electronic patrol system are strategically and scientifically installed in front of and behind houses, in green areas, and along walkways throughout the community. These devices record the time each patrol member reaches the device in detail and accurately, impartially supervising each member to complete their patrol duties according to the predetermined routes and time intervals, effectively ensuring that patrol members reach any alarm point within the community within the stipulated time.
The third line of defense is the building intercom system: Visitor intercom systems are installed at the community entrances, building entrances, and the iron gates of each building entrance. When a visitor arrives at the community entrance, property security personnel call the resident to confirm that someone is home, and the resident verifies the visitor's identity before the visitor is allowed entry. Once inside, the visitor enters the resident's apartment number at the building entrance and confirms with the resident via intercom. The resident then remotely opens the ground floor electric security door to allow the visitor in. This intercom system is also connected to the community monitoring center, allowing for real-time communication.
The third line of defense is the most widely used and most important one. The following analysis mainly focuses on the wireless visual doorbell system based on the 802.11 protocol.
1. System Overall Structure Design and Working Principle
Currently, most building access control devices are simple controllable electronic switches, generally using wired control via voice interaction. They lack visualization and wireless control capabilities, resulting in poor interactive effects, cumbersome wired network cabling, and insufficient intelligence. With the rapid development of video encoding/decoding and wireless transmission technologies, intelligent building systems have also developed rapidly. Embedded wireless network products, with their advantages of small size, low cost, and flexible and convenient use, are increasingly widely used. As the market for intelligent buildings continues to heat up, doorbell systems have become an important component of intelligent offices and intelligent communities. This study introduces a wireless visual doorbell system for intelligent communities, designed based on the 802.11 wireless network protocol, under this application prospect. As shown in Figure 1, the system uses the low-power, high-performance embedded IDT RC32434 as the main control chip, uses the VW2010 chip for hardware real-time encoding/decoding to improve encoding/decoding efficiency, and uses the PHILIPS BGW200 wireless chip for audio and video stream forwarding control. The entire system consists of a server and a client, mainly realizing audio and video data acquisition, high-quality encoding/decoding, and wireless network transmission functions.
(1) Server-side working principle
The input signals from the CCD sensor and audio port are converted into video and audio data via A/D conversion, followed by MPEG4 video encoding and MPEG MP3 audio encoding. The encoded video and audio streams are then sent to the network multiplexing module for packaging, and the compressed data stream is then delivered to the client via the 802.11x wireless network.
(2) Working principle of the system client
The audio and video stream data received from the wireless network is demultiplexed by the network demultiplexing module. The resulting video and audio streams are then sent to the video decoding module and audio decoding module, respectively, for MPEG4 video decoding and MP3 audio decoding. The decoded data is then sent to the visual terminal for display after video analog encoding, D/A conversion, and audio D/A conversion.
2. System Hardware Components
The system's hardware design is mainly divided into four parts: main control system, audio and video acquisition system, multimedia encoding and decoding system, and wireless network system.
2. System Software Design
The software design of this system is mainly divided into three layers: system initialization and booting and embedded system kernel porting, peripheral driver writing (including USB camera driver, wireless network module driver, etc.), and data acquisition and wireless transmission.
(1) System booting, kernel porting and file system establishment
(2) USB camera driver
(3) Audio and video data acquisition
(4) Audio and video compression and encoding/decoding
(5) Wireless Network Module Driver
Three Summaries
Through the study of the Building Automation course, I gained a systematic understanding of the definition and composition of intelligent buildings, a deep understanding of building automation systems, and mastered the working principles of air conditioning systems, water supply and drainage systems, and fire protection systems. This deepened my understanding of the professional courses I have studied in automation and laid a solid theoretical foundation for my future development.
The core idea of building automation is to replace manual thinking and operation with a control center that can control the normal operation of various equipment in a building. This helps people automatically monitor and control mechanical equipment; automatically adjust various equipment according to external conditions, environmental factors, and load changes; detect and promptly handle various unexpected emergencies; achieve unified management and coordinated control of various machines within the building; and manage energy and equipment, including equipment records. The building automation control system adopts a distributed computer control system based on modern control theory, commonly known as a distributed control system (DCS). It organically combines the real-time data collected by the controlled variables from the field via a microcomputer control device (DDC), the control tasks, the Ethernet topology transmission network of the acquisition bus network, and the core device—the central processing unit—enabling them to cooperate smoothly at a holistic level. Building automation technology in my country is still in a stage of rapid development. With people's continuous pursuit of a high-quality life and the continuous updating of science and technology, more advanced automation technologies will be applied to this field. With the development of computer technology, network technology, control technology, and communication technology, the system integration of intelligent buildings is moving towards networking and informatization, which will undoubtedly bring safety, comfort, and great convenience to people's lives.
