I REALLY NEED HELP!!! PLEASE!?

Forum 2005-2010 (read only) General Frequently-Asked Questions
1

Is it even posable to make a line following robot with just 2 Photo-Resistors?

int pRL = 2;

int pRR = 0;
int RL;
int RR;
int R1;
int R2;
       
void setup(void) {

  Serial.begin(9600);   
}

void loop(void) {
  #define DIFF 25 
  RL = analogRead(pRL);  
 
  RR = analogRead(pRR);
  R1 = (RR-DIFF);
  R2 = (RR+DIFF);
  if(RL > (RR-DIFF) && RL < (RR+DIFF)){
   Serial.println("Go");
  }
  if(RL < R1 || RL > R2){
   Serial.println("Left");
  }else{
   Serial.println("Right");
  } 
  
  

  
  delay(100);
}

it works for turning left, but as soon as its suppose to go straight, it says forward and right. is there any posable logic to make this work?

2

Is it even posable to make a line following robot with just 2 Photo-Resistors?

Well, you'll need some motors and some kind of controller, but yes. :smiley:
I've even seen line followers with only one photo-sensor.

R1 = (RR-DIFF);
  R2 = (RR+DIFF);
  if(RL > (RR-DIFF) && RL < (RR+DIFF)){

Why bother calculating R1 and R2 if you don't use them?

Can I introduce you to "abs" (nothing to do with tummy muscles)
http://arduino.cc/en/Reference/Abs

(Uncompiled, untested)

const int deadBand = 25;
const int leftPin = 2;
const int rightPin = 0;
      
void setup(void) 
{
  Serial.begin(9600);  
}

void loop(void) 
{
  int diff = analogRead(leftPin) - analogRead(rightPin);

  if(abs (diff) < deadBand) { // "equal" illumination
    Serial.println("Go");
  } else {
    if(diff < 0){
      Serial.println("Left"); // or vice versa
    }else{
       Serial.println("Right");
    }
  }
  delay (100);  
}