LDR example for DFRobot Arduino

LDR-example.ino

const int speedPin_M1 = 5;     //M1 Speed Control
const int speedPin_M2 = 6;     //M2 Speed Control
const int directionPin_M1 = 4;     //M1 Direction Control
const int directionPin_M2 = 7;     //M1 Direction Control
const int LDR = A0;  // Analog input pin that the potentiometer is attached to

int speedMotors = 0;
const int slow = 50;
const int fast =255;

const int dark = 200;
const int ambi = 500;
const int light = 800;
const int hyst = 50;

void setup() {
}


void loop() {
  int  light = analogRead(LDR);
  if ( light > 650 ) {
    speedMotors = map(light, 650, 800, slow, fast);
    carAdvance( speedMotors, speedMotors);
  }
  else if ( (light < 650) && (light > 300) ) {
    carStop();
  }
  else if (light < 250) {
    carBack( fast, fast );
  }
}

void carStop() {                //  Motor Stop
  digitalWrite(speedPin_M2, 0);
  digitalWrite(directionPin_M1, LOW);
  digitalWrite(speedPin_M1, 0);
  digitalWrite(directionPin_M2, LOW);
}
void carBack(int leftSpeed, int rightSpeed) {       //Move backward
  analogWrite (speedPin_M2, leftSpeed);             //PWM Speed Control
  digitalWrite(directionPin_M1, HIGH);
  analogWrite (speedPin_M1, rightSpeed);
  digitalWrite(directionPin_M2, HIGH);
}
void carAdvance(int leftSpeed, int rightSpeed) {     //Move forward
  analogWrite (speedPin_M2, leftSpeed);
  digitalWrite(directionPin_M1, LOW);
  analogWrite (speedPin_M1, rightSpeed);
  digitalWrite(directionPin_M2, LOW);
}
void carTurnLeft(int leftSpeed, int rightSpeed) {    //Turn Left
  analogWrite (speedPin_M2, leftSpeed);
  digitalWrite(directionPin_M1, LOW);
  analogWrite (speedPin_M1, rightSpeed);
  digitalWrite(directionPin_M2, HIGH);
}
void carTurnRight(int leftSpeed, int rightSpeed) {    //Turn Right
  analogWrite (speedPin_M2, leftSpeed);
  digitalWrite(directionPin_M1, HIGH);
  analogWrite (speedPin_M1, rightSpeed);
  digitalWrite(directionPin_M2, LOW);
}