Obstacle Avoidance Robotic Vehicle

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Obstacle Avoidance Robotic Vehicle

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Abstract

The main scope of project is to automatically changing the direction of robotic vehicle as required whenever any obstacle comes on its way.

Here an ultrasonic sensor is used which detects the presence of any obstacle and sends the signal to microcontroller which changes the direction of the robot.






Introduction

This particular robotic device is a combination of both mechanical and electronics engineering.

This system is made so that it can be used to detect and avoid obstacles successfully.

This robot will be just like an electronic car that keeps on moving in straight line until something comes in its path that’s when it decides to turns into some other direction so it successfully avoids the obstacle.






Block diagram






Working of circuit diagram

The project proposes robotic vehicle that has an intelligence built in it such that it guides itself whenever an obstacle comes ahead of it.

This robotic vehicle is built, using a microcontroller of 8051 family. An ultrasonic sensor is used to detect any obstacle ahead of it and sends a command to the microcontroller.

Depending on the input signal received, the microcontroller redirects the robot to move in an alternate direction by actuating the motors interfaced to it through a motor driver IC.






Hardware requirements

POWER SUPPLY

MICROCONTROLLER 8052

ULTRASONIC SENSOR

MOTOR DRIVER IC






230 V AC 50 Hz

Bridge rectifier

Filter(470µf)

5v Regulator

5V DC

12V step down transformer

Power supply






8K Bytes of In-System Programmable (ISP) Flash

Memory.

4.0V to 5.5V Operating Range.

Crystal Frequency 11.0592MHZ.

Three-level Program Memory Lock.

256 x 8-bit Internal RAM.

32 Programmable I/O Lines.

Three 16-bit Timer/Counters.

AT89S52

Micro controller






CPU

On-chip RAM

On-chip ROM for program code

4 I/O Ports

Timer 0

Serial PortOSC

Interrupt Control

External interrupts

Timer 1

Timer/Counter

Bus Control

TxD RxDP0 P1 P2 P3

Address/Data

Counter Inputs

Block diagram of MC






MC components explanation

ROM:

A code of 4K memory is incorporated as on-chip ROM in 8051.

RAM:

The 8051 microcontroller is composed of 128 bytes of internal RAM.

Interrupt Control:

An event which is used to suspend or halt the normal program execution for a temporary period of time in order to serve the request of another program or hardware device is called an interrupt.







Parallel Input/Output Ports:

PORT P0: When there is no external memory present, this port acts as a general purpose input/output port.

PORT P1: This port is used for various interfacing activities.

PORT P2: This port can be used as a general purpose port when there is no external memory but when external memory is present it works in conjunction with PORT PO as an address bus.

PORT P3: PORT P3 behaves as a dedicated I/O port.







Address Bus:

A bus is group of wires using which data transfer takes place from one location to another within a system.

Timers and Counters:

Synchronization among internal operations can be achieved with the help of clock circuits which are responsible for generating clock pulses.

Internal operations can be synchronized using clock circuits which produce clock pulses.






Pin diagram of 8052






8052 pin diagram explanation

Port 0(p0.0 to p0.7):

It is 8-bit bi-directional I/O port. It is bit/ byte addressable. During external memory access, it functions as multiplexed data and low-order address bus AD0-AD7.

Port 1 (p1.0 to p1.7):

It is 8-bit bi-directional I/O port. When logic '1' is written into port latch then it works as input mode. It functions as simply I/O port and it does not have any alternative function.






8052 pin diagram explanation

Port 2 (p2.0 to p2.7):

It is 8-bit bi-directional I/O port. It is bit/ byte addressable.

Port 3(p3.0 to port 3.7):

It is 8-bit I/O port. In an alternating function each pins can be used as a special function I/O pin.

RESET:

It is active high I/P signal. It should be maintained high for at least two machine cycle while oscillator is running then 8051 microcontroller resets.






Ultrasonic sensor

Ultrasonic sensors (also known as transceivers) work on a principle similar to radar or sonar which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively.

Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor.






Ultrasonic generators use piezoelectric materials such as zinc or lead zirconium tartrates or quartz crystal.

The material thickness decides the resonant frequency when mounted and excited by electrodes attached on either side of it.

The medical scanners used for abdomen or heart ultrasound are designed at 2.5 MHz In this circuit, a 40 kHz transducer is used for object detection in the air medium.

Ultrasonic receiver






Ultrasonic features

Use for motion or distance sensing .

Frequency: 40kHz ±1.0kHz.

Aluminum case.

Capacitance: 2000Pf ±20%.

Transmitter: bandwidth 5.0kHz/100Db, sound pressure level.

112Db/40 ±1.0kHz






Motor driver IC

L293D is a dual H-bridge motor driver integrated circuit (IC).

Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal.

This higher current signal is used to drive the motors.

L293D contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC motors can be driven simultaneously, both in forward and reverse direction.






Motor driver ic diagram






Operation of motor driver

L293D has 2 set of arrangements where one set has input 1, input 2, output 1 and output 2 and other set has input 3, input 4, output 3 and output 4, according to block diagram if pin no 2 & 7 are high then pin no 3 & 6 are also high.

If enable 1 and pin number 2 are high leaving pin number 7 as low then the motor rotates in forward direction.







Operation of motor driver

If enable 1 and pin number 2 are low leaving pin number 7 as high then the motor rotates in reverse direction.







Operational diagram






Software requirements

Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.

Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.






Applications

Obstacle Detection for a Mining Vehicle.

Driverless vehicles running along beams.

Obstacle detecting system for a motor vehicle.

Autonomous cleaning robot.

http://www.edgefxkits.com/obstacle-avoidance-robotic-vehicle






Future scope

The future work includes the enhancement of the robot design so that it can compute area of a room and plot it on the computer.






Conclusion

It gives on an opportunity to test his mechanical and electronics and programming skills .

Obstacle Avoidance Robotic Vehicle project also provides robot construction experience to beginners.

This technology has application everywhere from industry to home appliances all that is required is to implement it correctly to get the best out of it.

http://www.edgefxkits.com/obstacle-avoidance-robotic-vehicle





Obstacle Avoidance Robotic Vehicle

Engineering

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