System Overview

2.1 Over view of Microcontroller

             89C51 is main component in our project which is used for the purpose of receiving the serial data and send and actuating the relay to control the stepper motor.

2.1.1 ATMEL 89c51 Microcontroller

             The AT89c51 (shown in figure 2.1 ) contains a non-volatile FLASH program memory that is parallel programmable. For devices that are serial programmable (In System Programmable (ISP) with a boot loader).

             Both families are single-chip 8-bit Microcontroller manufactured in advanced CMOS process and are derivatives of the 89c51 Microcontroller family. All the devices have the same instruction set as the 80c51. The Pin diagram of 89c51 is shown in the figure 2.2.

2.1.2 Features

• Speed up to 33 MHz
• RAM expandable externally to 64 k bytes
• 4 level priority interrupt
• 6 interrupt sources
• Four 8-bit I/O ports
• Full-duplex enhanced UART
• Framing error detection
• Automatic address recognition
• Power control mode
• Clock can be stopped and resumed
• 3 16-bit timers
• Second DPTR register
• Asynchronous port reset

Figure 2.1: AT89C51 IC

               In 40 pin AT89C51, there are four ports designated as P₁, P₂, P₃ and P₀. Port P₀ and P₂ are also used to provide low byte and high byte addresses, respectively, when connected to an external memory. Port 3 has multiplexed pins for special functions like serial communication, hardware interrupts, timer inputs and read/write operation from external memory. AT89C51 has an inbuilt UART for serial communication. It can be programmed to operate at different baud rates. Including two timers & hardware interrupts, it has a total of six interrupts.

Figure 2.2: Pin Diagram of AT89c51 Microcontroller

2.2 LDR

         LDR is used in our project as a LASER light turned light sensor near the boundary to detect any intruder.

2.2.1 Circuit Description

          Two cadmium sulphide (cds) photoconductive cells with spectral responses similar to that of the human eye. The cell resistance falls with increasing light intensity. Applications include smoke detection, automatic lighting control and batch counting and burglar alarm systems. The schematic diagram of LDR is shown in the figure 2.3.

2.2.2 Features

• Camera exposure control.
• Auto slide focus-dual cell.
• Photocopy machines-density of toner.
• Colorimetric test equipment.
• Densitometer.
• Electronic scales-dual cell.
• Automatic gain control-modulated light source.
• Automatic Headlight dimmer.

Figure 2.3 : Pin diagram of 89c51 LDR

2.3 Encoder

            HT12E encoder is used in this project to Encode the password entered to control the automatic Weaponry Mechanism.

2.3.1 Circuit Description

            The 212 encoders are a series of CMOS LSIs for remote control system applications. They are capable of encoding information which consists of N address bits and 12-N data bits. Each address/data input can be set to one of the two logic states. The programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium upon  receipt of a trigger signal. The schematic diagram of HT12E is shown in the figure 2.4.

2.3.2 Features

• Operating voltage.
• 2.4 v-5v for the HT12A.
• 2.4v-12v for the HT12E.
• Low power and High noise immunity CMOS technology.
• Low standby current :0.1A (typ.) at VDD=5v
• HT12A with a 38 KHz Carrier for infrared transmission medium minimum transmission word.
• Four words for the HT12E.
• One word for the HT12A. 

Figure 2.4: HT12E Encoder Pin Diagram.

2.4 Decoder

          HT12D Decoder is used in this project at receiver to decode the transmitted data from transmitter.

2.4.1 Circuit Description

          The 212 decoders are a series of CMOS LSIs for remote control system applications. They are paired with Holteks212 series of encoders (refer to the encoder/decoder cross reference table). For proper operation, a pair of encoder/decoder with the same number of addresses and data format should be chosen.

The decoder receive serial addresses and data from a programmed 212 series of encoders that are transmitted by a carrier using an RF or an IR transmission medium. They compare the serial input data three times continuously with their local addresses. The schematic diagram of HT12D is shown in the figure 2.5.

2.3.2 Features

• Operating voltage: 2.4v-12v.
• Low standby current.
• Capable of decoding 12bits of information.
• Binary address setting.
• Low power and High noise immunity CMOS Technology. 

Figure 2.5: HT12D Decoder pin diagram.

2.5 Dual driver/receiver

           MAX232 dual driver/receiver is used for voltage levels, for compatible with the TTL voltage levels.

2.5.1 Circuit Description

           The MAX232 is a dual driver/receiver that includes a capacitive voltage generator to supply TIA/EIA-232-F voltage levels from a single 5v supply. Each receiver converts TIA/EIA-232-F input to 5v TTL/CMOS levels. These receivers have a typical threshold of 1.3v,  typical hysteresis of 0.5v, and can accept +/-30v inputs. Each driver converts TTL/CMOS input levels into TIA/EIA-232-F levels. The driver, receiver, and voltage-generator functions are available as cells in the Texas Instruments LinASIC Library. The schematic diagram of MAX232 is shown in the figure 2.6.

2.5.2 Features

• Operates from a single 5v power supply with 1.0F charge pump capacitors.
• Operator up to 120 Kbps.
• Two drivers and two receivers.
• +/- 30v input levels.
• Low supply current 8mA typical.
• ESD protection Exceeds JESD 22. 

Figure 2.6: MAX232 PIN Diagram.

2.6 Ultra Small Transmitter

         TLP434A is used in this project to transmit the encoded data to enable or disable the gun action.

2.6.1 Circuit Description

           These modules operate on 433.92, 418 or 315MHz,same as the standard TLP434 module but they made significant change in the size of the unit .They are seeing based and offer about 100 meters range in line-of-sight operating from 2-12volts. The new version has a data rate of 4.8 Kbps, over doubles the speed of the previous version and still provides 16DBm of output power off under 20mA of current. The module uses ASK as the form of modulation and has both digital and analogue outputs. The schematic diagram of TLP434 is shown in the figure 2.7.

2.6.2 Features

• Frequency range : 433.92 MHz
• Modulate mode: ASK
• Circuit shape: S/F
• Data rate: 8 Kbps

Figure 2.7: TLP434 Ultra small Transmitter Pin diagram.

    2.7 SAW Based Receiver

            RLP434A Saw based receiver is used in this project to receive the transmitted data and it is sent to decoder.

       2.7.1 Circuit Description

            These modules operate on 433.92, 418 or  315MHz, same as the standard RLP434 module but they made significant change in the size of the unit .They are seeing based and offer about 100 meters range in Line-of-sight operating from 2-12 volts. The new version has a data rate of 4.8 Kbps, over doubles  the speed of the previous version and still provides 16DBm of output power off under 20mA of current. The module uses ASK as the form of modulation and has both digital and analogue outputs. The schematic diagram of RLP434 is shown in the figure 2.8.

  

     2.7.2 Features

•        Frequency range : 433.92 MHz.
•        Modulate Mode : ASK
•        Circuit shape: LC
•        Data rate : 4800bps.
•        Sensitivity : -106 dBm.
•        Supply voltage : 5v

Figure 2.8: RLP434A Saw based Receiver pin diagram.

     2.8 High Voltage and High Current Darlington Transistor Array

         ULN2003 Darlington Transistor array is used in our Project to switching the Inductive loads.

     2.8.1 Circuit Description

         The ULN2003 is a monolithic high voltage and high current Darlington transistor arrays. It consists of seven NPN Darlington pairs that features high voltage outputs with common cathode clamp diode for switching inductive loads. The collector Current rating of a single Darlington pair is 500mA. The Darlington may be paralleled for higher current capability, Application include relay drivers, hammer drivers, lamp drivers, display drivers ( LED gas discharge), line drivers, and logic buffers. The schematic diagram of ULN2003 is shown in the figure 2.9.

  

     2.8.2 Features

•         500mA rated collector current (single output).
•         High voltage outputs : 50 V
•         Inputs compatible with various types of logic.

Figure 2.9: ULN2003 Pin Diagram.

     2.9 Connector

           DB9 Connector is used in our project to upgrade an RS232 port to an active USB port.

     2.9.1 Circuit Description

           The DB9-USB-RS232 connector can be used to upgrade an RS232 port to an active USB port      without the need to redesign the PCB. These active connectors contain all the USB to RS232 (and  vice-versa) conversion electronics and are designed to fit directly into the same PCB footprint as a    PC compatible RS232DB9 connector.

                                      The FTDI DB9-USB-RS232 connectors come in two types DB9-USB-RS232_M  and DB9-USB-RS232-F. The Schematic diagram of DB9 is shown in the figure 2.9.

     2.9.2 Features

•       RS-232 data signals: TxD, RxD, RTS, CTS, DSR, DTR, DCD, RI and GND.
•        Powered by USB port, No external Power Adapter required.
•        Serial port speed up to 1Mbps.

Figure 2.10: DB9 Connector pin diagram.

     2.10 Power Supply

           Switched Mode Power supply (SMPS) is used in this project to get 5V and 12V constant DC.

     2.10.1 Circuit Description

           The KA3501 is complete  housekeeping circuits for use in the secondary side of SMPS (Switched  Mode Power Supply). This IC (Integrated Circuit) contains a precision voltage reference, protection  circuits and a power good single generator. It also has a high current drive output for use in  conjunction with an external "Crowbar" SCR. The Schematic diagram of SMPS is shown in the  figure 2.11.

     2.10.2 Features

•      Complete House Keeping Circuit.
•      Few External Components.
•      Positive voltage Protection.
•      Negative Voltage Protection.

Figure 2.11: SMPS Pin Diagram.

     2.11 Uni-polar  Stepper Motor

          Stepper motor using C51 used in this Project to control the movement of LASER pointer toward the intruder.

     2.11.1 Circuit Description

           C51/C251 microcontroller output pins cannot directly drive stepper motor. These have to be    powered before being applied to stepper motor. These documents explains use the programmable    array counter (PCA) of the microcontroller to generate the control signals to the power interface.

                                            Interrupt response time does not affect the accuracy of the output. The Schematic diagram of stepper motor is shown in the figure 2.12.

     2.11.2 Features

•     The rotation angle of the motor is proportional to the input pulse.
•     The motor has full torque at standstill(if the winding are energize).
•     Precise positioning and repeatability of movement since good stepper motors have an accuracy   of 3-5% of a step and this error is non-cumulative from one step to the next.

Figure 2.12: Stepper Motor mechanism.

    2.12 Camera

           Creative sync  used as sensor to input the image of area under surveillance and it acts as a vision to the computer.

     2.12.1 Circuit Description

           Forget about complicated driver installation computer and you are good to go. enjoy .Simply plug  in the live.cam sync webcam into your ultra-smooth video playback with the live.

     Featuring a password protection feature which prevents unauthorized webcam, the live sage of the  cam sync even lets you enjoy 30burst shorts photo capture. share your videos capture on the live cam  sync effortless on YouTube and photo bucket with is one click function. The schematic of camera is  shown in figure 2.13.

     2.12.2 Features

•      Sensor: VGA (640 X 480) CMOS image sensor.
•      Video Resolution: Up to ( 800  X 600)pixels.
•      Picture Resolution: Up to  1.3 Mega pixels.
•      Frame rate: Up to 30fps at 800 X 600 pixels.
•     Works with native Windows drivers for  instant plug & play.

Figure 2.13: Creative sync.