Please help me out with the code on obstacle detecting robo-car!!

Using Arduino Programming Questions
#1

Hi,

I am trying to build an obstacle detecting robocar with the help of arduino uno. The other components used are an H-bridge with L298-N motor driver, a servo motor and HC SR-04(UV sensor). On powering the system, The car keeps on rotating in a circle and am failing to detect the fault in the code. This is the code

#include <Servo.h>
int motorpin1=7;
int motorpin2=6;
int motorpin3=4;
int motorpin4=5;
int servopin=11;
int trigpin=12;
int echopin=3;
int ena=9;
int enb=10;
long duration;
int distance=0;
int leftdist=0;
int rightdist=0;
int object=10;
Servo myservo;
void setup()
{
  myservo.attach(11);
  pinMode(motorpin1,OUTPUT);
  pinMode(motorpin2,OUTPUT);
  pinMode(motorpin3,OUTPUT);
  pinMode(motorpin4,OUTPUT);
  pinMode(trigpin,OUTPUT);
  pinMode(echopin,OUTPUT); 
  pinMode(ena,OUTPUT);
  pinMode(enb,OUTPUT); 
}

void loop()
{
  myservo.write(115);
  delay(700);
  analogWrite(ena,255);
  analogWrite(enb,255);
  delay(50);
  distance=readping();
  if(distance<=20)
  {
    movestop();
    delay(300);
    backward();
    delay(400);
    movestop();
    delay(300);
    rightdist=lookright();
    delay(300);
    leftdist=lookleft();
     delay(300);
     if(distance>leftdist)
     {
      turnright();
      movestop(); 
     }
     else
     {
      turnleft();
      movestop(); 
     }
    
  }
  else
  {
    forward();  
  }
  distance=readping();
}

void forward()
{
  digitalWrite(motorpin1,HIGH);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,HIGH);
  digitalWrite(motorpin4,LOW);  
}
void movestop()
{
  digitalWrite(motorpin1,LOW);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,LOW);
  digitalWrite(motorpin4,LOW);  
}
void backward()
{
  digitalWrite(motorpin1,LOW);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,HIGH);
  digitalWrite(motorpin4,HIGH);
}
void turnright()
{
  digitalWrite(motorpin1,LOW);
  digitalWrite(motorpin2,HIGH);
  digitalWrite(motorpin3,LOW);
  digitalWrite(motorpin4,HIGH);
  delay(500);
  digitalWrite(motorpin1,HIGH);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,HIGH);
  digitalWrite(motorpin4,LOW);  
}
void turnleft()
{
  digitalWrite(motorpin1,HIGH);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,LOW);
  digitalWrite(motorpin4,HIGH);
  delay(500);
  digitalWrite(motorpin1,HIGH);
  digitalWrite(motorpin2,LOW);
  digitalWrite(motorpin3,HIGH);
  digitalWrite(motorpin4,LOW);    
}
int lookright()
{
  myservo.write(50);
  delay(500);
  int distance=readping();
  delay(100);
  myservo.write(115);
  return distance;
  delay(100);  
}
int lookleft()
{
  myservo.write(170);
  delay(500);
  int distance=readping();
  delay(100);
  myservo.write(115);
  return distance;
  delay(100);  
}
int readping()
{
  digitalWrite(trigpin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin,LOW);
  duration=pulseIn(echopin,HIGH);
  distance=duration*.034/2;
  return distance;
}

Please help me in detecting any sort of fault so that i can proceed with my project.
Any kind of help would be appreciated
Thank You!!

#2

What do your debug prints tell you?
Oh, wait . . .

Please remember to use code tags when posting code

#3

putting any kind of code after the return statement does nothing because the function has... well... returned to the place that called it.

 return distance;
  delay(100);

probably not your actual problem, just FYI

#4

I’m not going to study your code until you put it in code tags using the code </> button

However I see widespread use of delay() and that will prevent your program from being responsive. Have a look at how millis() is used to manage timing without blocking in Several things at a time

…R

#5