GANESH GADGETS: November 2017

LINE FOLLOWER Part 4 :Coding and Run

Coming to the final blog of Line Follower I have given the code for this,Copy this and directly paste it in Arduino IDE and modify according your needs.

Code is for only 3 sensor input and its good for Beginners.

Here's the Code:

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//Code is for 3 sensor input//code by-Https://ganeshgadgets.blogspot.com

int ena = 11;//a-LEFT motor PWM output
int enb = 10;//b-RIGHT motor PWM output
int ar = 12;//a reverse//
int af = 13;// aforward//
int bf = 9;//b forward//
int br = 8;//b reverse//

int s1 = 14, s2 =15, s3 =16; //3 sensors connected to analog a0,a1,a2 pins(digital equivalent)

void setup() {
// put your setup code here, to run once:
// declaring output pins
pinMode(ena,OUTPUT);// declaring output pins
pinMode(enb,OUTPUT);
pinMode(ar,OUTPUT);
pinMode(af,OUTPUT);
pinMode(bf,OUTPUT);
pinMode(br,OUTPUT);
// declaring input pins
pinMode(s1,INPUT);
pinMode(s2,INPUT);
pinMode(s3,INPUT);
}

void loop() {
// put your main code here, to run repeatedly:
//case-1 FORWARD
if((digitalRead(s1)==HIGH) && (digitalRead(s2)==LOW) && (digitalRead(s3)==HIGH))
{
digitalWrite(ena, HIGH);// BOTH ENABLE PIN WILL BE HIGH FOR ALL CASES
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);
digitalWrite(ar, LOW);
digitalWrite(bf, HIGH);
digitalWrite(br, LOW);
}
//case-2 SMOOTH TURN RIGHT
if((digitalRead(s1)==HIGH) && (digitalRead(s2)==HIGH) && (digitalRead(s3)==LOW))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);
digitalWrite(ar, LOW);
digitalWrite(bf, HIGH);// GIVING BOTH HIGH RESULTS IN STOPPING RIGHT MOTOR
digitalWrite(br, HIGH);
}
//case-3 SMOOTH TURN LEFT
if((digitalRead(s1)==LOW) && (digitalRead(s2)==HIGH) && (digitalRead(s3)==HIGH))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);// GIVING BOTH HIGH RESULTS IN STOPPING LEFT MOTOR
digitalWrite(ar, HIGH);
digitalWrite(bf, HIGH);
digitalWrite(br, LOW);
}
//case-4 STOP OR START
if((digitalRead(s1)==HIGH) && (digitalRead(s2)==HIGH) && (digitalRead(s3)==HIGH))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);// GIVING ALL HIGH BOTH MOTORS WILL BE STOPPED
digitalWrite(ar, HIGH);
digitalWrite(bf, HIGH);
digitalWrite(br, HIGH);
}
//case-5 STOP OR START
if((digitalRead(s1)==LOW) && (digitalRead(s2)==LOW) && (digitalRead(s3)==LOW))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);// GIVING ALL HIGH BOTH MOTORS WILL BE STOPPED
digitalWrite(ar, HIGH);
digitalWrite(bf, HIGH);
digitalWrite(br, HIGH);
}
//case-6 SHARP RIGHT TURN
if((digitalRead(s1)==HIGH) && (digitalRead(s2)==LOW) && (digitalRead(s3)==LOW))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);
digitalWrite(ar, LOW);
digitalWrite(bf, LOW);// THIS WILL REVERSE MOTOR B
digitalWrite(br, HIGH);
}
//case-7 SHARP LEFT TURN
if((digitalRead(s1)==LOW) && (digitalRead(s2)==LOW) && (digitalRead(s3)==HIGH))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, LOW);// THIS WILL REVERSE MOTOR A
digitalWrite(ar, HIGH);
digitalWrite(bf, HIGH);
digitalWrite(br, LOW);
}
//case-8 ANTINODE DETECT
if((digitalRead(s1)==LOW) && (digitalRead(s2)==HIGH) && (digitalRead(s3)==LOW))
{
digitalWrite(ena, HIGH);
digitalWrite(enb, HIGH);

digitalWrite(af, HIGH);//IGNORING ANTINODE CONDITION AND MOVING FORWARD
digitalWrite(ar, LOW);
digitalWrite(bf, HIGH);
digitalWrite(br, LOW);
}
}
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You can use more sensors in If Statement like;

if((digitalRead(s1)==HIGH) && (digitalRead(s2)==LOW) && (digitalRead(s3)==HIGH) && (digitalRead(s4)==HIGH) && (digitalRead(s5)==HIGH) && (digitalRead(s6)==HIGH))
{........}

You can add speed variation in :

analogWrite(ena, 200);//0-255
analogWrite(enb, 200);//0-255

This is end of line follower project. For more tech and projects follow me.

LINE FOLLOWER Part 3 : CONNECTING ALL TOGETHER AND CONCEPT

Coming to the part 3 all you need is-

Arduino UNO(you can use others also,but I prefer UNO for beginners)
Sensor Array(min 3 to max 5 numbers of ir sensors)
Motor Driver(L298 or any other)
Line follower Chassis
Two DC motors
Jumper Wires(male-female,female-female)
Wheels and an Castro Wheel(Multi directional wheel)

Connect all the Modules According to the diagram given below:-

Points Worth Noting:-

All the modules should have a common ground. Every time you add any module to your project you should add ground of module to the ground pin of Arduino.
Connect the enable of motor Driver to any of PWM pins(3,5,6,9,10,11). It will help you to control the speed of Motor.
If you don't want speed Control then add enable pin to 5V of motor Driver or Vin, it will then take max speed in default.
Put all your sensor input to the analog pins. Its more convenient and gracious. You can use these pins as analog(A0....A5) or as digital pins(14-19). Digital input is better for line follower.

Concept Behind the Line follower Algorithm:

I will discuss the concept or the idea that can you use easily. Suppose you have 3 sensors so there are total of 8 possibilities of sensor values.

" You can use the formula-2^(No. of sensors)"

If you are using 5 sensors then you have 2^5=32 possibilities.

Lets go in detail....

See the figure

The sensor give digital HIGH while on white surface and digital LOW on black surface or VICE VERSA if you have sensor of inverting mode(op-amp).
Here we are considering following black line on white surface.
Going case by case.

CASE	ACTION REQUIRED	LEFT MOTOR	RIGHT MOTOR
1	FORWARD	FORWARD	FORWARD
2	SMOOTH TURN RIGHT	FORWARD	STOP
3	SMOOTH TURN LEFT	STOP	FORWARD
4	STOP OR START	STOP OR FORWARD	STOP OR FORWARD
5	STOP OR START	STOP OR FORWARD	STOP OR FORWARD
6	SHARP RIGHT TURN	FORWARD	REVERSE
7	SHARP LEFT TURN	REVERSE	FORWARD
8	ANTINODE DETECT	STOP OR FORWARD	STOP OR FORWARD

For simplicity here speed control is not disscussed. You can do that using Enable pin and analogWrite(pin number, 0-255) in arduino codes.
Codes to the line follower bot is in next blog.