we r making wood body for the car to make it easy-moving.

The Line Follower sensor is an add-on for your RedBot that gives your robot the ability to detect lines or nearby objects. The sensor works by detecting reflected light coming from its own infrared LED. By measuring the amount of reflected infrared light, it can detect transitions from light to dark (lines) or even objects directly in front of it.

The sensor has a 3-pin header which connects directly to the RedBot Mainboard via female to female jumper wires. Use the included RedBot library to detect lines or objects. A mounting hole lets you easily connect one or more of these to the front or back of your robot chassis.

//Motor A
const int motorPin1 = 9; // Pin 14 of L293
const int motorPin2 = 10; // Pin 10 of L293
//Motor B
const int motorPin3 = 6; // Pin 7 of L293
const int motorPin4 = 5; // Pin 2 of L293

//This will run only one time.
void setup(){

//Set pins as outputs
pinMode(motorPin1, OUTPUT);
pinMode(motorPin2, OUTPUT);
pinMode(motorPin3, OUTPUT);
pinMode(motorPin4, OUTPUT);

//Motor Control - Motor A: motorPin1,motorpin2 & Motor B: motorpin3,motorpin4

//This code  will turn Motor A clockwise for 2 sec.
analogWrite(motorPin1, 180);
analogWrite(motorPin2, 0);
analogWrite(motorPin3, 180);
analogWrite(motorPin4, 0);
delay(5000); 
//This code will turn Motor A counter-clockwise for 2 sec.
analogWrite(motorPin1, 0);
analogWrite(motorPin2, 180);
analogWrite(motorPin3, 0);
analogWrite(motorPin4, 180);
delay(5000);

//This code will turn Motor B clockwise for 2 sec.
analogWrite(motorPin1, 0);
analogWrite(motorPin2, 180);
analogWrite(motorPin3, 180);
analogWrite(motorPin4, 0);
delay(1000); 
//This code will turn Motor B counter-clockwise for 2 sec.
analogWrite(motorPin1, 180);
analogWrite(motorPin2, 0);
analogWrite(motorPin3, 0);
analogWrite(motorPin4, 180);
delay(1000);    

//And this code will stop motors
analogWrite(motorPin1, 0);
analogWrite(motorPin2, 0);
analogWrite(motorPin3, 0);
analogWrite(motorPin4, 0);

}

void loop(){

}

his battery level indicator offers (5) LEDs that light up progressively as the voltage increases:

Red: Power Connected (0%)
Yellow: Greater than 10.5V (25%)
Green 1: Greater than 11.5V (50%)
Green 2: Greater than 12.5V (75%)
Green 3: Greater than 13.5V (100%)

Operation of the battery level indicator

D1 is the voltage reference zener. Tied to this is a string of divider resistors (R2-6) that set the various fixed voltage levels. R7 & 8 form a voltage divider to that reduces the battery voltage by a factor of 3. U1 is an LM339 quad comparator that compares the various voltages from the two dividers. The comparator sections have open collector outputs that simply function as switches to operate the LEDs. D7 protects against reverse battery connection.

The LEDs are biased to operate at about 4mA which is quite bright if modern LEDs are used. This current can be adjusted simply by varying the series resistors (R9 through R13). The overall current drain as shown is about 25mA which tends to be wasteful for continuous operation. For energy conservation, connect to battery via a pushbutton (Push to Test).

the motor take so much power so we r trying to find better motor

motor driver is based on the very popular L298 Dual H-Bridge Motor Driver IC. This module will allow you to easily and independently control two motors of up to 2A each in both directions.

It is ideal for robotic applications and well suited for connection to a microcontroller requiring just a couple of control lines per motor.

the car worked will but battery was really weak