Dualmode Obstacle Avoidance Robot Content

8/13/2019 Dualmode Obstacle Avoidance Robot Content

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1 DUAL MODE OBSTACLE AVOIDANCE ROBOT

Dept. of ECE MANGALAM COLLEGE OF ENGINEERING

1. INTRODUCTION

In todays world robotics is fast growing and interesting field. It is simplest wayfor latest technology modification. So we decided to work on robotics field, and design

something which will make human life simpler in day today aspect. Real-time obstacle

avoidance is one of the key issues to successful applications of mobile robot systems. All

mobile robots feature some kind of collision avoidance, ranging from primitive algorithms

that detect an obstacle and steer the robot short of it in order to avoid a collision, through

sophisticated algorithms, that enable the robot to detour obstacles. The latter algorithms are

much more complex, since they involve not only the detection of an obstacle, but also takeappropriate decision concerning movement. Once these have been determined, the obstacle

avoidance algorithm needs to steer the robot around the obstacle and resume motion toward

the original target. The inspiration behind this project was to learn new things regarding our

domain. We wanted to do a project that was creative and practical but at the same time cost

effective... The main objectives of this project are;

i. To design a Mobile Robot with an ability to avoid obstacle

ii. To develop a mobile robot using PIC microcontroller and infrared sensor

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 in automatic mode that keeps on

moving in straight line until something comes in its path thats when it decides to turns into

some other direction so it successfully avoids the obstacle. We have used two dc gear motors

to give motion to the robot. Motor driver ICs are used for driving this dc motors in both

directions. The robot has an onboard infrared sensor module to detect the obstacles. The maincontroller of the robot is implemented in a PIC microcontroller. The algorithms runs on the

PIC microcontroller based on the information received from the remote control and

information from the infrared sensors. A RF-based remote control is used to control the

manual mode and automatic mode functions of the robot. The base chosen for this robot is

metallic with three wheels. The electronic parts used in the robot circuits are easily available

and cheap too.


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2. BLOCK DIAGRAM

2.1. REMOTE CONTROLE

2.2. ROBOT


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3. BLOCK DIAGRAM DESCRIPTION

The block diagram for remote control consists of switches, HT12 encoder and RF

transmitter. Micro switches are used for inputting the binary values to HT12 encoder which

converts parallel datas in to serial data. The output from the HT12encoder is transmitte d

using RF transmitter which uses ASK transmission method. The robotic bloc diagram consists

of RF reciver, HT12 decoder, PIC microcontroller, IR sensor, motor driver and two dc gear

motors. The RF receiver output is converted to parallel output using HT12 decoder. Which is

inputted to the microcontroller also microcontroller receive input from the IR sesors.The

program runs inside the microcontroller based on the obstacle avoidance algorithm

converts these inputs into output to drive the motors in the appropriate direction with the

help of motor diver ICs.The detailed explanation of each block is given below.

3.1. PIC MICROCONTROLLER

We have selected PIC microcontroller based on the following factors:-

Availability of IC burner

IC burner for PIC16F877A was available in our hand.

Availability of software development tool.

The software we are used is MPLABIDE and HI-TECH PIC compiler

I/O ports

5 I/O ports were available for PIC16F877A.

Also factors like speed, availability, in built ADC, cost of microcontroller and technical

support available is leaded us to select PIC16F877A.

PIC is a family of modified Harvard architecture microcontrollers made by

Microchip Technology, derived from the PIC1650 [1] [2] [3] originally developed by General

Instrument's Microelectronics Division. The name PIC initially referred to "Peripheral

Interface Controller".

Microcontroller PIC16F877A is one of the PIC Family microcontroller which is

popular at this moment, start from beginner until all professionals. Because PIC16F877A


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have flash memory technology so that can be write-erase until thousand times. The

superiority this RISC Microcontroller compared to with other microcontroller 8-bit especially

at a speed of and his code compression. PIC16F877A have 40 pin by 33 path of

I/O.PIC16F877A perfectly fits many uses, from automotive industries and controlling home

appliances to industrial instruments, remote sensors, electrical door locks and safety devices.

It is also ideal for smart cards as well as for battery supplied devices because of its low

consumption

High-Performance RISC CPU has features like Only 35 single-word instructions

to learn ,All single-cycle instructions except for program branches, which are two-cycle,

Operating speed as DC 20 MHz clock input DC 200 ns instruction cycle ,Up to 8K x 14

words of Flash Program Memory, Up to 368 x 8 bytes of Data Memory (RAM), Up to 256 x8 bytes of EEPROM Data Memory and Pin out compatible to other 28-pin or 40/44-pin

PIC16CXXX and PIC16FXXX microcontrollers.

The Peripheral Features of PIC are 3 timers as Timer0: 8-bit timer/counter with 8-

bit prescaler,Timer1: 16-bit timer/counter with rescale, can be incremented during Sleep via

external crystal/clock and Timer2: 8-bit timer/counter with 8-bit period register, presale and

postscaler.Also have features like Two Capture, Compare, PWM modules, Synchronous

Serial Port (SSP) with SPI (Master mode) and I2C (Master/Slave),USART(Universal

Synchronous Asynchronous Receiver) Transmitter (USART/SCI) with 9-bit address

detection, Parallel Slave Port (PSP) 8 bits wide with external RD, WR and CS controls

(40/44-pin only) and Brown-out detection circuitry for Brown-out Reset (BOR)

The Analog Features of PIC are 10-bit, up to 8-channel Analog-to-Digital Converter

(A/D), and Analog Comparator module (Two analog comparators , Programmable on-chip

voltage reference (VREF) module , Programmable input multiplexing from device inputs and

internal voltage reference , Comparator outputs are externally accessible)

100,000 erase/write cycle Enhanced Flash program memory typical,1,000,000

erase/write cycle Data EEPROM memory typical, Data EEPROM Retention > 40 years, Self-

reprogrammable under software control, In- Circuit Serial Programming (ICSP) via two

pins, Single-supply 5V In-Circuit Serial Programming, Watchdog Timer (WDT) with its own

on-chip RC oscillator for reliable operation, Programmable code protection, Power saving

Sleep mode, Selectable oscillator options and In-Circuit Debug (ICD) via two pins are specialfeatures of PIC16F877A.


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Basic circuit for working of PIC is as follows:

Fig 3. 1:Basic circuit of PIC

There are 7 pins you should connect correctly. Likes others electronic component, thesupply pin is the most important. The ideal voltage for PIC16F877A is 5V (Direct Current). It

should not be higher than 5.5V because it going to blow up. It also should not be less then 2V

because it not going to be operates.pin 11 and pin 32 are connected to vcc.pin 11 and pin 32

are connected to ground. The other important pin is Reset pin (MCLR - Master Clear Reset at

Pin number 1). If PIC read 0V at MCLR pin, it will reset the program, so if you not connect

the MCLR pin with 5V, PIC will remain reset and your program will not execute. You can

directly connect the MCLR with 5V (series with resistor likes picture below) but you willunable to reset if your system goes wrong. If you want to use the reset function, you need to

create logic condition which is 1 and 0 to the reset pin. 1 is mean the reset pin get 5V. If the

reset pin logic is 1, then the program in your PIC will execute, but if the reset pin logic

condition is 0 (which is 0V) then your PIC will not execute the program. As in above circuit,

when the switch is not pushed, current will flow trough 10K resistor and MCLR Pin. As a

result, MCLR Pin receives 5V and PIC read it as logic 1. But when switch is push, current

will flow through 10K resistor, switch and directly to ground. There is no voltage will receive

at MCLR Pin. This gives 0 logic at MCLR Pin. Now there are only 2 pin left which is pin


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number 13 and 14. Those pin was named as OSC1 and OSC2. You can connect the crystal

oscillator from various frequencies. Pulse generated from the oscillator will some time have

the noise. To reduce the noise, two capacitors in Pico farad value are needed. The value of

capacitor is depending on the speed of oscillator that you use. In our circuit we are using

4MHz crystal.

3.2. RF (ASK) MODULE

The RF module, as the name suggests, operates at Radio Frequency. The

corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the

digital data is represented as variations in the amplitude of carrier wave. This kind of

modulation is known as Amplitude Shift Keying (ASK).

Transmission through RF is better than IR (infrared) because of many reasons.

Firstly, signals through RF can travel through larger distances making it suitable for long

range applications. Also, while IR mostly operates in line-of-sight mode, RF signals can

travel even when there is an obstruction between transmitter & receiver. Next, RF

transmission is more strong and reliable than IR transmission. RF communication uses a

specific frequency unlike IR signals which are affected by other IR emitting sources.

Amplitude-shift keying (ASK ) is a form of amplitude modulation that represents digital data

as variations in the amplitude of a carrier wave.

Fig 3. 2: ASK communication system

Any digital modulation scheme uses a finite number of distinct signals to represent digital

data. ASK uses a finite number of amplitudes, each assigned a unique pattern of binary digits.

Usually, each amplitude encodes an equal number of bits. Each pattern of bits forms the


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symbol that is represented by the particular amplitude. The demodulator, which is designed

specifically for the symbol-set used by the modulator, determines the amplitude of the

received signal and maps it back to the symbol it represents, thus recovering the original data.

Frequency and phase of the carrier are kept constant.

Like AM, ASK is also linear and sensitive to atmospheric noise, distortions,

propagation conditions on different routes in PSTN, etc. Both ASK modulation and

demodulation processes are relatively inexpensive. The ASK technique is also commonly

used to transmit digital data over optical fiber. For LED transmitters, binary 1 is represented

by a short pulse of light and binary 0 by the absence of light. Laser transmitters normally

have a fixed "bias" current that causes the device to emit a low light level. This low level

represents binary 0, while a higher-amplitude light wave represents binary 1.The ask

demodulation is a two stage process that is recovery of the band limited bit stream and

regeneration of the binary bit stream.

Fig 3. 3: ASK sample waveform

The simplest and most common form of ASK operates as a switch, using the

presence of a carrier wave to indicate a binary one and its absence to indicate a binary zero.

This type of modulation is called on-off keying, and is used at radio frequencies to transmit

Morse code (referred to as continuous wave operation),


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Fig 3. 4:ASK module

This RF module comprises of an RF Transmitter and an RF Receiver . The

transmitter/receiver (Tx/Rx) pair operates at a frequency of 434 MHz an RF transmitter

receives serial data and transmits it wirelessly through RF through its antenna connected at

pin4. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received

by an RF receiver operating at the same frequency as that of the transmitter.

The RF module is often used along with a pair of encoder/decoder. The encoder is used for

encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E-

HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs.

The advantages of ASK over FSK are

ASK transmitters are simpler than FSK ASK transmitter current is 50% lower than FSK FSK transmission requires 1.5 times the bandwidth compared to ASK ASK receiver sensitivity is equal to or better than FSK


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Properly implemented, ASK receiver performance in the presence of co-channel

interference is generally better than FSK

3.3. MOTOR DRIVER IC L293D

Generally, even the simplest robot requires a motor to rotate a wheel or

performs particular action. Since motors require more current then the microcontroller pin

can typically generate, you need some type of a switch (Transistors, MOSFET, Relay etc.,)

which can accept a small current, amplify it and generate a larger current, which further

drives a motor. This entire process is done by what is known as a motor driver . Motor driver

is basically a current amplifier which takes a low-current signal from the microcontroller and

gives out a proportionally higher current signal which can control and drive a motor. In most

cases, a transistor can act as a switch and perform this task which drives the motor in a

single direction. Turning a motor ON and OFF requires only one switch to control a single

motor in a single direction. In order to rotate the motor in reverse direction we needed to

change polarity. This can be achieved by using four switches that are arranged in an

intelligent manner such that the circuit not only drives the motor, but also controls its

direction .This is called H bridge circuit.L239D IC is a motor driver with H Bridge. L293D IC

generally comes as a standard 16-pin DIP (dual-in line package). This motor driver IC can

simultaneously control two small motors in either direction; forward and reverse with just 4

microcontroller pins (if you do not use enable pins) Some of the features (and drawbacks) of

this IC are: .

1. Output current capability is limited to 600mA per channel with peak output current

limited to 1.2A (non-repetitive). This means you cannot drive bigger motors with this

IC. However, most small motors used in hobby robotics should work. If you areunsure whether the IC can handle a particular motor, connect the IC to its circuit and

run the motor with your finger on the IC. If it gets really hot, then beware... Also note

the words "non-repetitive"; if the current output repeatedly reaches 1.2A, it might

destroy the drive transistors.

2. Supply voltage can be as large as 36 Volts. This means you do not have to worry

much about voltage regulation.


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3. L293D has an enable facility which helps you enable the IC output pins. If an enable

pin is set to logic high, then state of the inputs match the state of the outputs. If you

pull this low, then the outputs will be turned off regardless of the input states

4. The datasheet also mentions an "over temperature protection" built into the IC. This

means an internal sensor senses its internal temperature and stops driving the motors

if the temperature crosses a set point

5. Another major feature of L293D is its internal clamp diodes. This fly back diode

helps protect the driver IC from voltage spikes that occur when the motor coil is

turned on and off (mostly when turned off)

6. The logical low in the IC is set to 1.5V. This means the pin is set high only if the

voltage across the pin crosses 1.5V which makes it suitable for use in high frequency

applications like switching applications (up to 5KHz)

7. Lastly, this integrated circuit not only drives DC motors, but can also be used to drive

relay solenoids, stepper motors etc.

Fig 3. 5:L293D pin out

The circuit shown to the above is the most basic implementation of L293D IC.The

pins are explained below.

1. Pin1 and Pin9 are "Enable" pins. They should be connected to +5V for the drivers to

function. If they pulled low (GND), then the outputs will be turned off regardless of

the input states, stopping the motors. If you have two spare pins in your


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microcontroller, connect these pins to the microcontroller, or just connect them to

regulated positive 5 Volts.

2. Pin4, Pin5, Pin12 and Pin13 are ground pins which should ideally be connected to

microcontroller's ground.

3. Pin2, Pin7, Pin10 and Pin15 are logic input pins. These are control pins which should

be connected to microcontroller pins. Pin2 and Pin7 control the first motor (left);

Pin10 and Pin15 control the second motor (right).

4. Pin3, Pin6, Pin11, and Pin14 are output pins. Tie Pin3 and Pin6 to the first motor,

Pin11 and Pin14 to second motor

5. Pin16 powers the IC and it should be connected to regulated +5Volts

6. Pin8 powers the two motors and should be connected to positive lead of a secondary

battery. As per the datasheet, supply voltage can be as high as 36 Volts.

Truth table for the circuit is as follows.

Pin 1 Pin 2 Pin 7 FunctionHigh High Low Turn Anti-

clockwise(Reverse)

High Low High Turn clockwise(Forward)

High High High StopHigh Low Low StopLow X X Stop

High ~+5V, Low ~0V, X=either high or low (don't care).

In the above truth table you can observe that if Pin1 (E1) is low then the motor stops,

irrespective of the states on Pin2 and Pin7. Hence it is essential to hold E1 high for the driver

to function, or simply connect enable pins to positive 5 volts with Pin1 high, if Pin2 is sethigh and Pin7 are pulled low, then current flows from Pin2 to Pin7 driving the motor in anti-

clockwise direction? If the states of Pin2 and Pin7 are flipped, then current flows from Pin7

to Pin2 driving the motor in clockwise direction.


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3.4. OTHER COMPONENTS

3.4.1. HT12E/HT12D

HT12E is an encoder integrated circuit of 212

series of encoders. They are paired with 212

series of decoders for use in remote control system applications. It is mainly used in

interfacing RF and infrared circuits. The chosen pair of encoder/decoder should have same

number of addresses and data format.

Simply put, HT12E converts the parallel inputs into serial output. It encodes the 12

bit parallel data into serial for transmission through an RF transmitter. These 12 bits are

divided into 8 address bits and 4 data bits. HT12E has a transmission enable pin which is

active low. When a trigger signal is received on TE pin, the programmed addresses/data are

transmitted together with the header bits via an RF or an infrared transmission medium.

HT12E begins a 4-word transmission cycle upon receipt of a transmission enable. This cycle

is repeated as long as TE is kept low. As soon as TE returns to high, the encoder output

completes its final cycle and then stops.

HT12D is a decoder integrated circuit that belongs to 2 12 series of decoders. In

simple terms, HT12D converts the serial input into parallel outputs. It decodes the serial

addresses and data received by, say, an RF receiver, into parallel data and sends them to

output data pins. The serial input data is compared with the local addresses three times

continuously. The input data code is decoded when no error or unmatched codes are found. A

valid transmission in indicated by a high signal at VT pin.

The operating voltage for both encoder and decoder is 2.4v to 12v.this ic uses Low

power and high noise immunity CMOS technology.

3.4.2. IR TRANSMISSION AND DETECTION

Here we are using IR LED as transmitter and photo

detector as reciever.An IR LED, also known as IR

transmitter, is a special purpose LED that transmits

infrared rays in the range of 760 nm wavelength. Such

LEDs are usually made of gallium arsenide or aluminium

gallium arsenide. They, along with IR receivers, are

Fig 3. 6: Ir detection


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commonly used as sensors.The appearance is same as a common LED. Since the human eye

cannot see the infrared radiations, it is not possible for a person to identify whether the IR

LED is working or not, unlike a common LED. To overcome this problem, the camera on a

cell phone can be used. The camera can show us the IR rays being emanated from the IR

LED in a circuit. Here we are using photo diode as IR detector along with a resistance. Since

when IR fall on the photo diode its conducting and voltage is developed across t he

resistance. This voltage is used along with a comparator to act as a IR detector section.

3.4.3. COMPARATOR

LM324 is a 14pin IC consisting of

four independent operational amplifiers (op-amps)

compensated in a single package. Op-amps are high

gain electronic voltage amplifier with differential

input and, usually, a single-ended output. The

output voltage is many times higher than the

voltage difference between input terminals of an op-

amp.

These op-amps are operated by a single power supply LM324 and need for a dual

supply is eliminated. They can be used as amplifiers, comparators, oscillators, rectifiers etc.

The conventional op-amp applications can be more easily implemented with LM324.In our

application we used it as a comparator in order to compare the input voltage from the IR

sensor module to a reference value, which will help us to adjust the obstacle detection range.

3.4.4. POWER SUPPLY

In our circuit we are using 9V battery for remote control and 12V rechargeable battery

for robotic section. In robotic section some parts need 5V dc source. For that we are using

IC7805.

Fig 3. 7: LM324 pin out


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7805 is a voltage regulator integrated circuit. It is a member of 78xx

series of fixed linear voltage regulator ICs. The voltage source in a

circuit may have fluctuations and would not give the fixed voltage

output. The voltage regulator IC maintains the output voltage at a

constant value. The xx in 78xx indicates the fixed output voltage it is

designed to provide. 7805 provides +5V regulated power supply.

Capacitors of suitable values can be connected at input and output pins

depending upon the respective voltage levels. In our robot IC 7805 is used in receiver robotic

section since main supply is 12v.

4. CIRCUIT DIAGRAM

4.1. REMOTE CONTROL

Fig 3. 8:LM7805 pin out


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4.2. ROBOT

4.3. MOTOR DRIVER PROTECTION CIRCUIT


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5. WORKING

5.1. REMOTE

The main parts of this remote are micro switches, HT12E encoder and RF transmitter

.The function of encoder is to convert the parallel bits input from the switches to serial bit

format, allows it to transmit via RF transmitter.

By default all the parallel input to the encoder is set high. When a switch is pressed the

corresponding bit goes low by grounding them. Each bit pattern is assigned for movement in

particular direction and also to select mode of operation. The bit pattern generated is assigned

as follows in transmitter section as.

BIT PATTERN OPERATION

0111 Forward movement

1011 Reverse movement

1101 Left movement

1110 Right movement

0011 Enter to automatic mode

1100 Exit from automatic mode

When user fed a bit pattern via micro switches say 0111, its parallel input to the

HT12E encoder input pins such as AD8, AD9, AD10 and AD11 respectively. The encoder IC

sends this bit pattern in serial format as 0 1 1 1...to RF transmitter through pin no 17

(Dout) to the pin no 2 of the RF transmitter. The chosen pair of encoder/decoder should have

same number of addresses and data format. These 12 bits are divided into 8 address bits and

4 data bits. HT12E has a transmission enable pin which is active low. When a trigger signal

is received on TE pin, the programmed addresses/data are transmitted together with the

header bits via an RF transmission medium. HT12E begins a 4-word transmission cycle upon

receipt of a transmission enable. This cycle is repeated as long as TE is kept low. As soon as

TE returns to high, the encoder output completes its final cycle and then stops. Here address

assigned for encoder is 00000000 via address pins A1 to A7 by grounding them.


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RF transmitter actually works based on ASK (Amplitude Shift Keying) or OOK (On

Off keying) technique. By doing manipulations on the bit patterns it produces corresponding

signal waves at 433MHz for transmission. The transmission occurs at the rate of 1Kbps -

10Kbps.The power supply used is 9V battery.

5.2.ROBOT

The robotic circuit consist of RF reciver,HT12D decoder,PIC microcontroller,IR

module,LM324 comparator,L239D motor driver IC and voltage regulator IC 7805.The

transmitted RF signal is decoded by ASK receiver. . The demodulator, which is designed

specifically for the symbol-set used by the modulator, determines the amplitude of the

received signal and maps it back to the symbol it represents, thus recovering the original data.

Frequency and phase of the carrier are kept constant. In this circuit we uses 15C.M. antenna

at transmitter and receiver.

From the data pin of the RF receiver input is given to Din of HT12D decoder. The

address of the decoder is same as that of encoder as 00000000.Hence it decodes the serial bits

from the RF receiver module into parallel bit. The serial input data is compared with the local

addresses three times continuously. The input data code is decoded when no error or

unmatched codes are found. A valid transmission in indicated by a high signal at VT pin.Thus we get parallel outputs from pin D8 to D11 respectively.

The output from the decoder is fed to RA0 to RA3 pins of PIC16F877A

microcontroller. This is PORTA of the PIC microcontroller. Also PIC microntroller receive

input from the IR receiver through pins RC4 and RC5 respectively. Which are pins of

PORTC. The IR module consists of IR LED and IR receiver which is a photo diode. The IR

receiver produces a voltage when there is any obstacle. This voltage is compared with a

reference voltage using a comparator IC LM324.The reference voltage is set using a

potentiometer. This comparator helps us to fix the distance at which obstacle has to be

detected. This comparator has 4 OP-amps inside them and we are using only two of them.

This input is actually given as IR module input to RC4 and RC5.The obstacle detection can

be identified by the user using two LED lights at the output of the comparator.

The program runs in the PIC microcontroller based on the obstacle avoidance

algorithm. The program runs and produces the corresponding output for input to run the

motor in the either clockwise or anti-clockwise direction. The rotation of motor in either


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direction is achieved by motor driver IC L293D.The output of PIC microcontroller is PORTD

and we are using four pins RD0,RD1,RD2 and RD3.The various output assigned are.

BIT PATTERN OPERATION

1010 Forward Movement

0101 Backward Movement

0110 Left Movement

1001 Right Movement

The output from the PIC microcontroller are given to motor driver IC input pins2,7,10 and 15 respectively. . Motor driver is basically a current amplifier which takes a low-

current signal from the microcontroller and gives out a proportionally higher current signal

which can control and drive a motor. In order to rotate the motor in reverse direction we

needed to change polarity. .This is called H bridge circuit.L239D IC is a motor driver with H

Bridge. At the output of the motor driver pins 3, 6 and 11, 14 two 12v dc geared motor are

connected. This motor has high torque3 and gives motion to the robot. (The detailed working

of motor driver is given in chapter).The reference voltage for motor driver is 12V. Here weare using some a voltage regulator IC 7805 which is a 5v regulator IC since components need

5V as vcc and we are using 12V rechargeable battery.

5.2.1. MANUAL MODE

The default mode of operation is manual mode. In which the user needs to give each

and every instruction manually by pressing each key assigned for robotic movement. When

user presses key for to take a deviation towards left or right direction the robot isprogrammed to take exactly 90degree deviation towards left or right. Manual mode of

operation provides user to control the vehicle .Thus the control of the vehicle by user can be

extended up to wide range depends on the range of operation of RF transmitter-receiver

section.


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5.2.2. AUTOMATIC MODE

The main important feature of this robot is its ability to work in automatic mode.

Many robots are basically works fully under control of human. here is the importance of this

robot it enter and exit into the automatic mode by pressing corresponding switches and it

does not need any manual instruction further. This mode is applicable in conditions such as

when the range of operation exceeds maximum RF transmission range, when there robot is

out of human visibility and in hazards environments. When 0011 is transmitted robot

recognise it as command for transferring the mode from manual to automatic mode. In

automatic mode the robot moves forward and any obstruction is detected it stops and

works according to the obstacle avoidance algorithm. If we wanted exit from the automatic

mode by transmitting 1100.The algorithm is explained below.

5.3. ALGORITHM

The algorithm on which the PIC works is described as follows.PIC continuously

checks the bit patterns coming through the input. First algorithm checks the mode of

operation on which the robot has to works. The robot works in manual mode by default. In

manual mode .In manual mode it first checks whether there is any obstruction? If there is no

obstruction the robot can move in right ,left , forward and backward direction by checking

corresponding bit patterns(produced from transmitted bits and input from the IR module).If

any obstruction is encountered it suddenly stops and the forward movement is disabled but

left,rigt and backward movement are available. And repeat the above cycle in manual mode.


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Robot always checks mode of operation. When it entered into the automatic mode it moves

forward direction in a straight line if no obstruction is there. But any obstruction is

encountered the obstacle avoidance algorithm will run. That is firstly it stop then move

reverse , moves right after that it moves left and forward..Repeat the cycle until it avoids

obstruction.

6. PCB LAYOUT

Circuit board required for this project is simply constructed by homemade PCBfabrication steps with ferrous sulphate and copper cladd board.PCB layout is created using

Dip trace and net list is printed on a hard paper. Then the paper is fixed on the copper board

in such a way that the printed side and copper surface are in contact. Then it ironed using an

iron box for 8 minutes. This process will mask copper clad surface in the shape of net list.

Masking process is actually protects the copper from exposing it to chemical solution. Then

board is immersed in the ferrous sulphate solution which is made by dissolving 50gm of

FeSo4 in 500 ml of water. The board is immersed for 40 minutes which will remove thecopper content which is exposed to solution. Thus we will get the PCB. The mask is removed


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using thinner . After that component is placed according to circuit and soldered.The PCB

layouts of circuits is given below.

6.1. REMOTE

6.2. ROBOT


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6.3. PROTECTION CIRCUIT FOR MOTOR DRIVER IC

7. SOFTWARE TOOLS

The various software tools we are used are

1. DIP TRACE

Dip trace 2.3.1.0 provides very handy and easy to use tool for the PCB layout.

Many of its features were utilized leading to an accurate and efficient design. It has

design error check and electrical rool check tools which provide to be helpful in the

design. It is loaded with huge components list that is categorized in various librariesfor giving simplicity. Placement of component is also very easy & they can be rotated

in 360 degree to customize the design.

2. MPLAB IDE

MPLAB provides I.D.E for PIC programming and is very easy to use. We are

used MPLAB version 7.6 to program PIC microcontroller. We are user HI-TECH PIC

complier along with the MPLAB as compiler .This softwares are helpful to create

HEX file which is required for burning on to the PIC.It has powerful debugging tool

Which detect the most of the errors in the program?

3. PROTEUS

Proteus pro 7.6 was very helpful in the case of stimulation of PIC

microcontroller. In this software we could virtually burn the PIC and verify its

working using a simple circuit.PCB layout can be also created using this tool but

DIPTRACE were more advanced in PCB layout creation.


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8. ADVANTAGES

Robots can accomplish complicated or enormous projects more precisely than

humans can Robots- sometimes called "artificial intelligence" do many things faster thanhumans, and make everyday life safer. For example- The military has begun to use robots in

the warzones. Robots make everyday life more enjoyable.

Ability to Work in Environments that are Inhospitable to humans: This is an interesting

set of advantages of robotics. There are a number of tasks that are too dangerous, too exposed

to toxins, or just plain too dirty for humans to conveniently do them. These are ideal robotics

tasks. This includes tasks as simple as spray painting, because there is no need to worry about

the robot inhaling the paint fumes! It also includes such daunting tasks as defusing bombs

and such dirty tasks as cleaning sewers. They can do jobs in dangerous situations and save

lives of thousands of peoples.

Automatic control: The auto mode does not require human guidance. The robot has the

capability to find its on path, so it can be used for a particular task once the task is set it will

work automatically.

Quality and Accuracy of Work: Robotic systems have the capability of impressivelymeliorating the quality of work. They don't make any mistakes and errors as humans do. This

saves a lot of important output and production time. They provide optimum output in regards

to quality as well as quantity.

9.DISADVANTAGES

Limitations using IR module: Here we used IR module as the obstacle detecting system

although it has the advantages it holds some disadvantages like the receivers and transmitters

must be in direct line of sight of each other, high intensity or fluorescent lights cause

interference and the Quality varies with the company. The edge obstacles are sometimes not

detected this can be adjusted by placing more sensors.

Algorithm: The algorithm is perfect for small areas .its a basic model which needs further

development to present in complicated environment.


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Speed Control: In this model the robot works in a constant speed adjustment can be done on

further improvement of circuit.

Battery backup: Battery can be selected for task requirement but considering it as a wireless

robot recharging is a disadvantage

10. APPLICATION

This device has application in surveying different landscapes and mapping them. it can

also be used in commercial devices like

automated lawn mower

smart room cleaner etc

Some of the applications are mentioned below:

1. Obstacle Detection for a Mining Vehicle

Reliable obstacle detection is an essential element of an autonomous mining

vehicle system. An autonomous vehicle must be capable of detecting potentially dangerous

obstacles that would endanger the vehicle itself, other vehicles, personnel or expensive site

infrastructure while navigating through the mine. Autonomous vehicles will not be deployed

in the field alongside manned vehicles until robust obstacle detection systems have been

developed.

The development of robust obstacle detection systems for these vehicles is difficult because

of the relatively harsh conditions encountered in mining environments. The operating

environment could include rain, dust, mud, high humidity,diesel fumes (small particles),

extremes of temperature, severe vibration, extreme vehicle pitching and rolling, and bright

light sources (e.g. the sun).

2. Driverless vehicles running along beams

Behind obstacle detection as it stands today, and how it might fill the needs of

driverless vehicles running along beams. To replace the eyes and brains of a human driver

with equally good (or better) technological devices is very tricky. The human minds ability

to process sensory information is very advanced and complex. The research going on today

to make robots detect obstacles is very much based on how insects do the same

thing.


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The sensors of the obstacle detection systems that are of interest to us are built on different

technologies. Those that are available to us today are:

1. Infrared sensors

2. Common radar 3. Microwave-based radar

4. Digital cameras

5. Laser

6. Combination of digital cameras and laser

The present invention provides a digital ultrasonic obstacle detection system for vehicles,

which can tune reference data, which is the basis for the determination of whether an

obstacle has been detected. This system executes a parking assist mode or a tuning mode in

response to a command from an external master. The system is configured to store

reflected wave signal data received from a sensor unit, in memory and transmit the

reflected wave signal data to the external master via vehicle communication, at the time of

executing the tuning mode.

3. Obstacle detecting system for a motor vehicle

An obstacle detecting system for a motor vehicle which is capable of detecting not

only the distance to an obstacle(s) existing in front of the motor vehicle and the width there

of, but also its height to thereby allow a motor vehicle control to be effected more

appropriately with high reliability. The distance to the object and its width are detected by a

laser radar type distance detecting unit, while the distance to the object lying within a

window preset by a window setting device is also detected by a distance detecting circuit of

a stereoscopic video camera unit. An object size determining unit is provided for selecting a

window corresponding to a distance value detected by the stereoscopic video camera unit

and which coincides with a distance value calculated by the laser radar type distance

detecting unit, to thereby determine the size of the object on the basis of the preset

position of the selected window.


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4. Autonomous cleaning robot

This invention relates to an obstacle detection system for an autonomous

cleaning robot .There is a long felt need for autonomous robotic cleaning devices for

dusting, mopping, vacuuming, and sweeping operations. Although technology exists forcomplex robots which can, to some extent, "see" and "feel" their surroundings, the

complexity, expense and power requirements associated with these types of robotic

subsystems render them unsuitable for the consumer marketplace. It is therefore an object

of this invention to provide a robot obstacle detection system which is simple in design, low

cost, accurate, easy to implement, and easy to calibrate.

It is a further object of this invention to provide such a robot detection system

which prevents an autonomous cleaning robot from driving off a stair or over an obstacle

which is too high or too low is a further object of this invention to provide a robotic wall

detection system which is low cost, accurate, easy to implement and easy to calibrate.It is a

further object of this invention to provide such a robot wall detection system which effects

smoother robot operation in the wall following mode.

5. Fire fighting robot

We could use obstacle avoidance robot as a fire fighting robot by addingtemperature sensor, water tank and making some changes in the algorithm.

11. FUTURE SCOPE

Future scope of this robotic project is various application as described above.We

could add camera for surveillance,microphone can be implemented for voice recording,and

other sensors to improve obstacle detection.This robot can work in hazardous environments

were human cannot reach.If it implemented in vehicle such as mining,good transporting

vehicle etc it will improve its performance.This robot can be implemented in driver lessvehicle (like Google Car).


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12. CONCLUSION

Robotics is a rapidly growing field of technology in which the science tries to create a replica for

human brain in sense of intelligence and creativity. Scientists are try to build more and more

developed and multifunctional robot day by day. Here is our simple aim to build a simple version of

this intelligent robot which inelligent sense the obstructive condition in front of it and take suitable

decision based on them.

Here the not only a simple obstruction detection robot but also an avoidance robot which is

intelligently avoid the obstruction and find its path. The main brain part of this project is PIC

microcontroller ie, pic16f877a.the selection factors of PIC is depends on its special in built features

and availability etc. here the RF signal transmission, technique is used for communication between

transmitter and receiver. The movement is achieved with the help of two inexpensive dc motors

supplied from 12v battery.l293d driver is used for driving the motor.The obstruction is detected with

the help of two IR sensors and photodiodes. This method is always cheapest.

The peculiarity is this robot can work in both manual and automatic mode. This extends its

application to the region were the humans cannot reach. The transition between these modes can

be done with the help of simple commands . Along with the advantages it has some sort of

disadvantages also . The IR sensor used is very vulnerable to IR noise, since the IR reflection method

is used, small obstruction cannot be detected, the battery used must has better backup and so

on..These cons can be removed by better advancement of the robot by more efficient program or by

better sensing components . Hence we can conclude that robotics is a Vast area of research in which

more and more inventions are doing in day by day. So a simple project on this field is more capable

giving more awareness about it.

13. REFERANCE

www.efy.com

www.engineersgarage.com

www.wikipedia.com
http://www.efy.com/http://www.efy.com/http://www.engineersgarage.com/http://www.engineersgarage.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.engineersgarage.com/http://www.efy.com/


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14. APPENDIX A: PROGRAME

#include

void delay(int x)//delay function

{ int i,j;

for (i=0;i


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while(1)

{

if (RC4==0 && RC5==0 &&RA0==0 && RA1==1 && RA2==1 && RA3==1)

{

fw();

delay(10);

}

else if (RC4==0&&RC5==0&&RA0==1&&RA1==0&&RA2==1&&RA3==1)

{

back();

delay(10);}


{

right();

delay(10);

}


{

left();

delay(10);

}


{

back();

delay(10);

}


{

right();

delay(10);

}


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{

left();

delay(10);

}


{

while(1)

{

if (RC4==0&&RC5==0&&RA0==1&&RA1==1&&RA2==1&&RA3==1)

{while(1)

{r1:

if (RC4==1&&RC5==1&&RA0==1&&RA1==1&&RA2==0&&RA3==0)

{

goto re;

}

Elseif RC4==0&&RC5==0&&RA0==1&&RA1==1&&RA2==0&&RA3==0)

{

goto re;

}


{

fw();

delay(10);

}

else if ((RC4==1&&RC5==1&&RA0==1&&RA1==1&&RA2==1&&RA3==1))

{

stop();

delay(10);

back();

delay(50);


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right();

delay(34);

fw();

delay(50);

left();

delay(34);

goto r1;

}

}

}else

{

stop();

}

}

}

else

{

stop();

}

}

}


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15. APPENDIX B: DATA SHEETS


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