The Control System for Lighting Based on

The Control System for Lighting Based onSingle–chip MicrocomputerWith the rapid development of electronic technology, the system of control based on Single-chip Microcomputer is widely applied in industry, agriculture, electric power, electron, intelligent building and so on. Microcomputer, as the subject and core of the embedded system of control, replaces the traditional system—electronic circuit. At the same time, the development and maturation of the intelligent building have established the substantial foundation for the popularization and application of the control system for lighting based on single-chip microcomputer.The paper expatiates on the designing theories and implementation method of the control system for lighting by wired or wireless communications. Taking the designing process as mainline, it describes the process of designing from two respects—hardware and software. In another word, the paper describes the process from the method of circuit designing to the software technology of realizing the demanded functions. The host controller of the control system for lighting is based on AT89C51 single-chip microcomputer, and the auxiliary ones are based on AT89C2051. The system can do many jobs, such as wired communication, wireless data transmitting, controlling and display. The paper describes the designing process of the circuit at length, including: keyboard and LED display circuit, RS485 communication circuit, wireless transmitting circuit, control circuit of lighting, watchdog circuit, etc. The designing of software mainly includes the several programming, such as wired communication, wireless data transmitting, lamplight controlling, timed controlling, keyboard scanning and LED displaying. The wired communication programming function is that through Master-slave communication method based on RS485 the host controller sends orders to the all auxiliary controllers or each one, including: turning on lighting, turning off lighting, regulating brightness of lighting, controlling timed lighting, etc. The wireless data transmitting programming function is that by wireless transmitter it realizes wireless controlling of the lighting, and achieves the functions identical to wired communication.Traditional building automatic controlling system only includes such subsystems: comprehensive wires, computer network, safe defending, fire defending and closed-circuits TV monitoring systems and so on. But in the recent years, withthe economic development and the progress of the science and technology, people have put forward more higher demands for energy-conservation of lighting lamps and scientific management, which makes the lighting control system of the classroom have such functions as energy-conservation, convenience, intelligence, etc. What’s more, it can improve the efficiency of the work and study, result in many kinds of lighting effects, and improve the management level.There are the design philosophy of this system, operation principle of every chip, and such relevant problems as the choice, making and debugging of the components and unit circuits about lighting control system of classroom, which regards the micro-control unit as the control core of the system. This control system is suitable for such occasions as various kinds of multimedia classrooms, station waiting rooms, offices, etc. It is mainly composed of lightening control unit, moving sensor unit, illuminative sensor unit, handed-control unit, and so on. The target of the design is intelligent lightening, scientific management, and energy-conservation and cost- conservation. The AT89C2051 with the feature of cheap cost has been used as the control unit in the whole design.The whole system not only has been introduced in the paper, but also has been successfully finished with series of the Dais micro-control unit. The experiment suggests that this design can easily come true if the users do as the thesis. So it can be used as the intelligent lighting control system of the university campus. What’s more, it will affect better if combining with other intelligent control systems.LED SummaryLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.LED history50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, a total power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now,the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the 3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.In the 1960s, the use of science and technology workers semiconductor PN junction of The principle of developing a LED light-emitting diodes. At that time, the development of LED, the materials used are GaASP, its luminous color is red. After nearly 30 years of development, and now we are very familiar with the LED, has been sent to red, orange, yellow, green, blue, and other shade. However lighting necessary for white LED light only in recent years to develop, readers here to tell us about lighting with white LED.。