PROJECT ANALYSIS

HARDWARE

  MICROCONTROLLER

This PIC has 40 pins. For power supply pins, VDD has connected to dc voltage which is range around 4V - 6V while VSS is connecting to ground. Then, clock pins osc1 and osc2 connected to oscillator (resonator). Function MCLR pin is to reset the PIC. The remains pins are input and output. 

The microcontroller acts like the brain of the door security monitoring system. The purpose of Microcontroller PIC16F877A which is manufactured by Microchip is to get the input from keypad and controlling transmitter. This chip is selected based on several reasons.

                        i. Its size is small and equipped with sufficient output ports without having to use a decoder or multiplexer.

                        ii. Its portability and low current consumption.

                        iii. It has ADC inside the chip itself which allow to converting the signal (analog) from transmitter into digital code

                        iv. It is a very simple but powerful microcontroller. Users would only need to learn 35 single word instructions in order to program the chip.

                        v. It can be programmed and reprogrammed easily (up to 10,000,000 cycles) using the universal programmer in robotics lab. 

PIN CONNECTION OF PIC16F877A FOR DOOR SECURITY MONITORING SYSTEM

Pin name	Pin no	Description	Application
Vdd	11,32	Positive supply (+5V)	Power supply to chip
Vss	12,31	Ground references	Ground
Osc 1 & Osc 2	13 & 14	For oscillator or resonator	Connect to resonator 4 Mhz
MCLR	1	Reset input	Always connected to +5V
RE2	10	Input / output pin	Connect to enable input keypad
RC0-RC3	15-18		Connect to input keypad
RD0 – RD7	19-26	Input / output pin	Display in LCD
RB0, RB4,RB5	33,37-38	Register select, read & write and enable
RC6	25	Serial input transmitter	Transmitter
RB3	36	Input/ output port	Relay
RB1 & RB2	34-35	Input/ output port	Indicator (LED)