Microcontroller Based Digital Visitor Counter
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Microcontroller Based Digital Visitor Counter ABSTRACT
Digital visitor counter is a reliable circuit that takes over the task of counting number of Persons/ Visitors in the Room very accurately. When somebody enters into the Room then the Counter is Incremented by one. The total number of Persons inside the Room is displayed on the seven segment display module. The microcontroller does the above job it receives the signals from the sensors, and this signals operated under the control of software which is stored in ROM.
This project we will create counter system for apply. The total number of object is displayed on the seven segment display. The system is fully controlled by the 16 bit microcontroller 8051 which has a 4Kbytes of ROM for the program memory.
The proposed system is based on 8051 microcontroller which is in our syllabus.For doing this
project we use some of the software like Eagle software is used for designing the PCB for this project.(Since PCB making is a big process and involves lot of machineries which are expensive, we are going to outsource this to the manufacturer.)
IC8051 is one of the popular Microcontroller. It has only 20 pins and there are 15 input/output lines. The microcontroller has a program memory of 2 Kilobytes. The microcontroller continuously monitor the sensor feed and if somebody enters sensors will provide information to the data processing unit.This counter Sensor consist of 3 Section as follows:
Detect Object (Sensor), Data Processing (CPU) and final section Display by LCD module:
Detect Object (Sensor): Proximity sensor(infrared sensors)
Data Processing (CPU): For this project we choose microcontroller 8051
Display: For final section Display by seven segment display
Digital visitor counter is a reliable circuit that takes over the task of counting.Number of Persons/ Visitors in the Room very accurately. When somebody enters into the Room then the Counter is Incremented by one. The total number of Persons inside the Room is displayed on the seven segment display. The microcontroller does the above job it receives the signals from the sensors, and this signals operated under the control of software which is stored in ROM. You can reset the counter using switch
1. PROJECT DESCRIPTION
INTEL’S 8051 Architecture
The generic 8051 architecture sports a Harvard architecture, which contains two separate buses for both program and data. So, it has two distinctive memory spaces of 64K X 8 size for both program and data.
It is based on an 8 bit central processing unit with an 8 bit Accumulator and another 8 bit B register as main processing blocks. Other portions of the architecture include few 8 bit and 16 bit registers and 8 bit memory locations. Each 8051 device has some amount of data RAM built in the device for internal processing. This area is used for stack operations and temporary storage of data. This base architecture is supported with on chip peripheral functions like I/O ports, timers/counters, versatile serial communication port. So it is clear that this 8051 architecture was designed to cater many real time
The following list gives the features of the 8051 architecture:
Optimized 8 bit CPU for control applications.
Extensive Boolean processing capabilities.
64K Program Memory address space.
64K Data Memory address space.
128 bytes of on chip Data Memory.
32 Bi directional and individually addressable I/O lines.
Two 16 bit timer/counters.
Full Duplex UART.
6 source / 5 vector interrupt structure with priority levels.
On chip clock oscillator.
Now you may be wondering about the nonmentioning of memory space meant for the program storage, the most important part of any embedded controller. Originally this 8051 architecture was introduced with on chip, `one time programmable' version of Program Memory of size 4K X 8. Intel delivered all these microcontrollers (8051) with user's program fused inside the device. The memory portion was mapped at the lower end of the Program Memory area. But, after getting devices, customers couldn't change anything in their program code, which was already made available inside during device fabrication.
Central Processing Unit
The CPU is the brain of the microcontrollers reading user's programs and executing the expected task as per instructions stored there in.
Its primary elements are an 8 bit Arithmetic Logic Unit (ALU), Accumulator (Acc), few more 8 bit registers, B register, Stack Pointer (SP), Program Status Word (PSW) and 16 bit registers, Program Counter (PC) and Data Pointer Register (DPTR). The ALU (Acc) performs arithmetic and logic functions on 8 bit input variables. Arithmetic operations include basic addition, subtraction, multiplication and division. Logical operations are AND, OR, Exclusive OR as well as rotate, clear, complement and etc. Apart from all the above, ALU is responsible in conditional branching decisions, and provides a temporary place in data transfer operations within the device. B register is mainly used in multiply and divide operations. During execution, B register either keeps one of the two inputs or retains a portion of the result. For other instructions, it can be used as another general purpose register.
8051 has two 16 bit Timers/Counters capable of working in different modes. Each consists of a `High' byte and a `Low' byte which can be accessed under software.
There is a mode control register and a control register to configure these timers/counters in number of ways. These timers can be used to measure time intervals, determine pulse widths or initiate events with one microsecond resolution upto a maximum of 65 millisecond (corresponding to 65, 536 counts). Use software to get longer delays. Working as counter, they can accumulate occurrences of external events (from DC to 500KHz) with 16 bit precision.
In our project we are using 16 bit microcontroller 8051, it is the advanced 16 bit microcontroller from ATMEL, which incorporates Flash Rom, and Timer etc.
Features of 8051 microcontroller are:
RAM – 128 Bytes (Data memory)
ROM – 4Kbytes (ROM signify the on – chip program space)
Serial Port – Using UART makes it simpler to interface for serial communication
Two 16 bit Timer/ Counter
Input/output Pins – 4 Ports of 8 bits each on a single chip.
6 Interrupt Sources
8 – bit ALU (Arithmetic Logic Unit)
Harvard Memory Architecture – It has 16 bit Address bus (each of RAM and ROM) and 8 bit Data bus
8051 can execute 1 million one-cycle instructions per second with a clock frequency of 12MHz.
This microcontroller is also called as “System on a chip” because it has all the features on a single chip.
The AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2 Kbytes of Flash Programmable and erasable read only memory (PEROM).
The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with theindustry Standard MCS-51Ô instruction set and pinout. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control application