So here goes my 1st post 
I thought of building a line following robot using Arduino Uno Rev 3 (on a windows 7 laptop, incase its necessary) by following a tutorial.So I gathered all the required parts and theres this IR emitter/detector (which both of them are on a single pack) which gives me the problem.
I thought of testing everything on a breadboard before actualy beginning to build it. So I connected the IR sensor as instructed in the tutorial, the long leads to +5 of the arduino and the GND to the GND of the Arduino through a resistor. Then a wire from inbetween the GND of the detector and the resistor to an analog pin of the Arduino.
UPDATE : It just gives me 0 or 1 and when i cover it from my finger, it increases upto 25. I tried some other IR sensors of the same type, but nothing changes. Its just the same.
Note - I can use only the analog pins since I have to use the motorshield.
Heres the code : (Very sorry, I am putting the whole code)
// Linus the Line-bot
// Follows a Black line on a White surface (poster-board and electrical tape).
// Code by JDW 2010 – feel free to modify.
#include <AFMotor.h> // this includes the Afmotor library for the motor-controller
AF_DCMotor motor_left(1); // attach motor_left to the Adafruit motorshield M1
AF_DCMotor motor_right(3); // attach motor_right to the Adafruit motorshield M3
// Create variables for sensor readings
int sensor1 = 0;
int sensor2 = 0;
int sensor3 = 0;
int sensor4 = 0;
int sensor5 = 0;
// Create variables for adjusted readings
int adj_1 = 0;
int adj_2 = 0;
int adj_3 = 0;
int adj_4 = 0;
int adj_5 = 0;
// You can change the min/max values below to fine tune each sensor on your bot
int s1_min = 200;
int s1_max = 950;
int s2_min = 200;
int s2_max = 950;
int s3_min = 200;
int s3_max = 950;
int s4_min = 200;
int s4_max = 950;
int s5_min = 200;
int s5_max = 950;
// this threshold defines when the sensor is reading the black line
int lower_threshold = 20;
// value to define a middle threshold (half of the total 255 value range)
int threshold = 128;
// this threshold defines when the sensor is reading the white poster board
int upper_threshold = 230;
// this value sets the maximum speed of linus (255 = max).
// using a speed potentiometer will over-ride this setting.
int speed_value = 255;
// end of changeable variables
void setup()
{
Serial.begin(9600); // start serial monitor to see sensor readings
// declare left motor
motor_left.setSpeed(255);
motor_left.run(RELEASE);
// declare right motor
motor_right.setSpeed(255);
motor_right.run(RELEASE);
}
void update_sensors(){
// this will read sensor 1
sensor1 = analogRead(A0);
adj_1 = map(sensor1, s1_min, s1_max, 0, 255);
adj_1 = constrain(adj_1, 0, 255);
// this will read sensor 2
sensor2 = analogRead(A1); // sensor 2 = left-center
adj_2 = map(sensor2, s2_min, s2_max, 0, 255);
adj_2 = constrain(adj_2, 0, 255);
// this will read sensor 3
sensor3 = analogRead(A2); // sensor 3 = center
adj_3 = map(sensor3, s3_min, s3_max, 0, 255);
adj_3 = constrain(adj_3, 0, 255);
// this will read sensor 4
sensor4 = analogRead(A3); // sensor 4 = right-center
adj_4 = map(sensor4, s4_min, s4_max, 0, 255);
adj_4 = constrain(adj_4, 0, 255);
// this will read sensor 5
sensor5 = analogRead(A4); // sensor 5 = right
adj_5 = map(sensor5, s5_min, s5_max, 0, 255);
adj_5 = constrain(adj_5, 0, 255);
// check value for speed potentiometer if present (to read the pot, uncomment line below)
//speed_pot = analogRead(5) / 4;
}
void loop(){
update_sensors(); // update sensors
//speed_value = speed_pot; // Leave commented out, unless using potentiometer
// first, check the value of the center sensor
if (adj_3 < lower_threshold){
// if center sensor value is below threshold, check surrounding sensors
if (adj_2 > threshold && adj_4 > threshold){
// if all sensors check out, drive forward
motor_left.run(FORWARD);
motor_left.setSpeed(speed_value);
motor_right.run(FORWARD);
motor_right.setSpeed(speed_value);
}
// you want the bot to stop when it reaches the black box.
else if (adj_1 < 1){
if (adj_2 < 1){
if (adj_3 < 1){
if (adj_4 < 1){
if (adj_5 < 1){
// if all sensors are reading black, stop Linus.
motor_left.run(RELEASE);
motor_right.run(RELEASE);
}
}
}
}
}
}
// otherwise, the center sensor is above the threshold
// so we need to check what sensor is above the black line
else {
// first check sensors 1
if (adj_1 < upper_threshold && adj_5 > upper_threshold){
motor_left.run(RELEASE);
motor_left.setSpeed(0);
motor_right.run(FORWARD);
motor_right.setSpeed(speed_value);
}
// then check sensor 5
else if (adj_1 > upper_threshold && adj_5 < upper_threshold){
motor_left.run(FORWARD);
motor_left.setSpeed(speed_value);
motor_right.run(RELEASE);
motor_right.setSpeed(0);
}
// if not sensor 1 or 5, then check sensor 2
else if (adj_2 < upper_threshold && adj_4 > upper_threshold){
motor_left.run(RELEASE);
motor_left.setSpeed(0);
motor_right.run(FORWARD);
motor_right.setSpeed(speed_value);
}
// if not sensor 2, then check sensor 4
else if (adj_2 > upper_threshold && adj_4 < upper_threshold){
motor_left.run(FORWARD);
motor_left.setSpeed(speed_value);
motor_right.run(RELEASE);
motor_right.setSpeed(0);
}
}
///// Print values for each sensor
/////sensor 1 values
Serial.print("sensor 1: ");
Serial.print(sensor1);
Serial.print(" - ");
Serial.print("Adj 1: ");
Serial.print(adj_1);
Serial.print(" - ");
/////sensor 2 values
Serial.print("sensor 2: ");
Serial.print(sensor2);
Serial.print(" - ");
Serial.print("Adj 2: ");
Serial.print(adj_2);
Serial.print(" - ");
/////sensor 3 values
Serial.print("sensor 3: ");
Serial.print(sensor3);
Serial.print(" - ");
Serial.print("Adj 3: ");
Serial.print(adj_3);
Serial.print(" - ");
/////sensor 4 values
Serial.print("sensor 4: ");
Serial.print(sensor4);
Serial.print(" - ");
Serial.print("Adj 4: ");
Serial.print(adj_4);
Serial.print(" - ");
/////sensor 5 values
Serial.print("sensor 5: ");
Serial.print(sensor5);
Serial.print(" - ");
Serial.print("Adj 5: ");
Serial.print(adj_5);
Serial.print(" ");
Serial.print("speed: ");
//Serial.print(speed_pot);
Serial.println(" ");
}
// end of code
Sesnor :
Datasheet : http://www.vishay.com/docs/83760/tcrt5000.pdf
Setup:
It would be really great if someone can help me out here. This is my very first robotic project and I am a total beginner to this field eventhough I have some knowledge on programming stuff
I searched everywhere on the internet but couldn't find a solution.
Thanks alot
thanks alot for the tip to check the emitter and apparently its working. I updated the picture above 
