基于单片机的居室安全报警系统设计.doc

1、本科生毕业设计（论文）专业外文翻译原 文： Microcontroller Based Home Automation System With Security 译 文：基与单片机的智能家居系统与安全性 17Microcontroller Based Home Automation System With Security Abstract: With advancement of technology things are becoming simpler and easier for us. Automatic systems are being preferred over manual

2、 system. This unit talks about the basic definitions needed to understand the Project better and further defines the technical criteria to be implemented as a part of this project.Keywords-component; Automation, 8051 microcontroller, LDR,LED, ADC, Relays, LCD display, Sensors, Stepper motorI.NTRODUC

3、TIONA home automation system integrates electrical devices in ahouse with each other. The techniques employed in home automation include those in building automation as well as the control of domestic activities, such as home entertainment systems, houseplant and yard watering, pet feeding, changing

4、 the ambiance scenes for different events (such as dinners or parties), and the use of domestic robots. Devices may be connected through a computer network to allow control by apersonal computer, and may allow remote access from the internet.Typically, a new home is outfitted for home automation dur

5、ing construction, due to the accessibility of the walls, outlets, and storage rooms, and the ability to make design changes specifically to accommodate certain technologies. Wireless systems are commonly installed when outfitting a pre-existing house, as they reduce wiring changes. These communicate

6、 through the existing power wiring, radio, or infrared signals with a central controller. Network sockets maybe installed in every room like AC power receptacles. Although automated homes of the future have been staple exhibits for Worlds Fairs and popular backgrounds in science fiction, complexity,

7、 competition between vendors, multiple ncompatible standards and the resulting expense have limited the penetration of home automation to homes of the wealthy or ambitious hobbyists.II.HOME AUTOMATIONHome/office automation is the control of any or all electrical devices in our home or office, whethe

8、r we are there or away. Home/office automation is one of the most exciting developments in technology for the home that has come along in decades. There are hundreds of products available today that allow us control over the devices automatically, either by remote control; or even by voice command.

9、Home automation (also called domotics) is the residential extension of building automation. It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC (heating,ventilation and air conditioning), appliances, and other systems,to pr

10、ovide improved convenience, comfort, energy efficiency and security. Disabled can provide increased quality of life for persons who might otherwise require caregivers or institutional care. Earlier, we looked into the face of future when we talked about automated devices, which could do anything on

11、instigation of a controller, but today it has become a reality.III.NEED OF AUTOMATIONWith advancement of technology things are becoming simpler and easier for us. Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and se

12、rvices. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscularrequirements of work, automation greatly decreases the need for human sensory and mental requirements as well. Automatio

13、n plays an increasingly important role in the world economy and in daily experience. Automatic systems are being preferred over manual ystem. Through this project we have tried to show automatic control of a house as a result of which power is saved to some extent.a) An automated device can replace

14、good amount of human working force, moreover humans are more prone to errors and in intensive conditions the probability of error increases whereas, an automated device can work with diligence,versatility and with almost zero error.Replacing human operators in tasks that involve hard physical or mon

15、otonous work.Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities,underwater, etc)Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc.Economy improvement. Automation may improve in economy of enterprises, soc

16、iety or most of humankind. For example, when an enterprise that has invested in automation technology recovers its investment, or when a state or country increases its income due to automation like Germany or Japan in the 20th Century.b) This is why this project looks into construction and implement

17、ation of a system involving hardware to control a variety of electrical and electronics system.IV.SUPPY UNITA.Transformer:The main source of power(Fig 1) supply is a transformer. The maximum output power of power supply is dependent on maximum output power of transformer .We determine power from its

18、 current and voltage rating. e.g.: if there is a transformer of 12V, 500mA then maximum power delivered by transformer is 6Watt.It means we can drive a load from this transformer up to 6w. In our project our maximum power requirement is 1watt. So to provide this power we use 12V/250mA transformer. T

19、he maximum output power of this transformer is 4watt.it means it can easily drive load up to 4 watt.B.RectifierRectifier is a circuit which is used to convert ac to dc.Every electronic circuit requires a dc power supply for rectification. We have used four diodes.C.Input filter:After rectification w

20、e obtain dc supply from ac but it is not pure dc it may have some ac ripples .To reduce these ripples we use filters. It comprises of two filters low frequency ripple filter and high frequency ripple filter. To reduce low frequency ripples we use electrolytic capacitor. The voltage rating of capacit

21、or must be double from incoming dc supply. It blocks dc and passes ripples to ground.D.RegulatorInitial stage of every electronic circuit is power supply system which provides required power to drive the whole system. The specification of power supply depends on the power requirement and this requir

22、ement is determined by its rating. The main components used in supply system are.Regulator is a device which provides constant output voltage with varying input voltage. There are two types of regulators (a) Fixed voltage regulator(b) Adjustable regulatorWe have used fixed voltage regulator LM78XX l

23、ast two digits signify output voltage. The voltage for our system is 5V that is why we have used 7805 regulator which provides 5V from 12V dc.E.Output filter:It is used to filter out output ripple if any.F.Output indicationWe use LED to observe the functioning of our system. If he LED glows it confi

24、rms proper functioning of our supply.We have used four power supply units.This supply is for the microcontroller,display and relay unit.The microcontroller requires 5 volt supply to perform any desired task.G.Control UnitTwo control units were used one for internal system and one for external system

25、 and these control unit based on ATMELsAT89S52 microcontroller(Fig 2). The given capture shows the pins and basic requirement of microcontroller to make it functional. Detailed description of the controller is 100uf / 50v.In addition, the AT89S52 is designed with static logic for operation down to z

26、ero frequency and supports two software electable power saving modes. The Idle Mode stops the CPUwhile allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the nex

27、t interrupt or hardware reset.The Downloadable Flash can be changed a single byte at a time and is accessible through the SPI serial interface. Holding RESET active forces the SPI bus into a serial programming interface and allows the program memory to be written to or read from unless Lock Bit 2 ha

28、s been activated.H.FeaturesCompatible with MCS-51ProductsI.8KbytesofIn-SystemDownloadable Flash Memory ReprogrammableSPI Serial Interface for Program DownloadingEndurance: 1,000 Write/Erase Cycles4.0V to 5.5V Operating RangeFully Static Operation: 0 Hz to 33 MHz56 x 8 bit Internal RAM32 Programmable

29、 I/O LinesThree 16 bit Timer/CountersEight Interrupt SourcesUll Duplex UART Serial ChannelLow Power Idle and Power Down ModesI .Advantages Less power consumptionLow costLess space requiredHigh speedFig 2-Chip BoardAT89S52 is an ATMEL controller with the core of Intel MCS-51. It has same pin configur

30、ation as give above. The AT89S52 is a low-power, high-performance CMOS 8-bit microcomputer with 8K bytes of Downloadable Flash programmable and erasable read only memory and 2K bytes of EEPROM. The device is manufactured using Atmels high density nonvolatile memory technology and is compatible with

31、the industry standard 80C51 instruction set and pin out. The on-chip Downloadable Flash allows the program memory to be reprogrammed in-system through an SPI serial interface or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Downloadable Flash on a monolithi

32、c chip, the Atmel AT89S52 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.The AT89S52 provides the following standard features: 8K bytes of Downloadable Flash, 2K bytes of EEPROM, 256 bytes of RAM, 32 I/O lines, programma

33、ble watchdog timer, two Data Pointers, three 16-bit timer/counters, a six-vectorJ .Pin DescriptionVCC: Supply voltage. GND: Ground., Port 0: Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can b

34、e used as high impedance inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during

35、program verification. External pull-ups are required during program verification.Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull-ups and

36、can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups.In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respe

37、ctively, as shown in the following table .Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2: Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins

38、, they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses

39、to external data memory that uses 16-bit addresses (MOVX DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memory that uses 8-bit addresses (MOVX RI), Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives

40、 the high-order address bits and some control signals during Flash programming and verification. Port 3 Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the interna

41、l pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups. Port 3 receives some control signals for Flash programming and verification. Port 3 also serves the functions of various special features of the AT89S5

42、2.RST: Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. This pin drives high for 98 oscillator periods after the Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit DISR

43、TO,the RESET HIGH out feature is enabled. ALE/PROG: Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant r

44、ate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note,however, that one ALE pulse is skipped during each access to external data memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only du

45、ring a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSEN: Program Store Enable (PSEN) is the read strobe to external program memory. When the AT89S52 is executing code from external

46、program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPP: External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting a

47、t 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.XTAL1: Input to the inverting oscill

48、ator amplifier and input to the internal clock operating circuit.XTAL2: Output from the inverting oscillator amplifier.H. Display UnitFig 3-Display UnitLiquid crystal displays (LCD) is an alphanumeric display and widely used in recent years as compared to LEDs. This is due to the declining prices of

49、 LCD, the ability to display numbers, characters and graphics, incorporation of a refreshing controller into the LCD, their by relieving the CPU of the task of refreshing the LCD and also the ease of programming for characters and graphics. We have used JHD162A advanced version of HD44780 based LCDs.