get rid of all delays

Using Arduino Programming Questions
1

Hi.
I've been doing an obstacle avoidance robot.
It works fine.

It stops when obstacle is detected. turns. and goes again.

here's the code :

#include <NewPing.h>
#include <Servo.h>
 
Servo servoG;
Servo servoD;
Servo servoPan;

#define TRIGGER_PIN  12
#define ECHO_PIN  13
#define MAX_DISTANCE 400

const int dangerDist = 10;
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

int B = 0;
int A = 180;

 
void setup () {
Serial.begin (9600) ;
servoG.attach (9) ;
servoD.attach (10) ;
servoPan.attach (11);
servoPan.write (90);
delay (1000);


}
 
void loop () {

servoPan.write (90);
delay (500);
int uS = sonar.ping();
int dist = uS / US_ROUNDTRIP_CM ;
  
if (dist > dangerDist) {
  go ();
}
  else {
endgo ();
delay (500);
    
servoPan.write (140) ;
delay (500);
int uS140 = sonar.ping();
int dist140 = uS / US_ROUNDTRIP_CM ;


servoPan.write (40) ;
delay (500);
int uS40 = sonar.ping();
int dist40 = uS / US_ROUNDTRIP_CM ;

servoPan.write (120) ;
delay (500);
int uS120 = sonar.ping();
int dist120 = uS / US_ROUNDTRIP_CM ;

servoPan.write (60) ;
delay (500);
int uS60 = sonar.ping();
int dist60 = uS / US_ROUNDTRIP_CM ;
    
if ( uS60 + uS40 > uS120 + uS140 ) {
  endgo();
    backwards ();
    endgo();
    left ();
   }
else {
  endgo();
   backwards ();
   endgo();
  right();
  }
 
 }
}

 
void go () {
servoG.write(A) ;
servoD.write (B) ;
}
void endgo () {
servoG.write (90) ;
servoD.write (90) ;
delay (500);
}
void backwards () {
servoG.write (B) ;
servoD.write (A) ;
delay (800);
}
void left () {
servoG.write (B) ;
servoD.write (B) ;
delay (500);
}
void right () {
servoG.write (A) ;
servoD.write (A) ;
delay (500);
}

I would like now to get rid of all delays so that I can do multiple tasks at the same time. and also - for my personnal understanding on how to to use millis () correctly instead of delays.

I tried this code which I thought would work. But I have absolutely not the same result.
The robot goes forward. hi head moves but it won't stop or turn.

What did I do wrong ? and how can I use just ONE easy : if (currenttimewheels - previoustimewheels > ...).

here's my new code :

#include <NewPing.h>
#include <Servo.h>
 
Servo servoG;
Servo servoD;
Servo servoPan;
int B = 0;
int A = 180;

#define TRIGGER_PIN  12
#define ECHO_PIN  13
#define MAX_DISTANCE 400
const int dangerDist = 10;
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

unsigned long currrenttimewheels = 0;
unsigned long previoustimewheels = 0; 
long waittimewheels = 5000; 

 
void setup () {
Serial.begin (9600) ;
servoG.attach (9) ;
servoD.attach (10) ;
servoPan.attach (11);
servoPan.write (90);
delay (1000);


}
 
void loop () {

unsigned long currenttimewheels = millis ();
  
servoPan.write (90);
delay (500);
int uS = sonar.ping();
int dist = uS / US_ROUNDTRIP_CM ;
  
if (dist > dangerDist) {
  go ();
}
  else {
   
endgo ();

    
servoPan.write (140) ;
delay (500);
int uS140 = sonar.ping();
int dist140 = uS / US_ROUNDTRIP_CM ;


servoPan.write (40) ;
delay (500);
int uS40 = sonar.ping();
int dist40 = uS / US_ROUNDTRIP_CM ;

servoPan.write (120) ;
delay (500);
int uS120 = sonar.ping();
int dist120 = uS / US_ROUNDTRIP_CM ;

servoPan.write (60) ;
delay (500);
int uS60 = sonar.ping();
int dist60 = uS / US_ROUNDTRIP_CM ;
    
if ( uS60 + uS40 > uS120 + uS140 ) {
  endgo();
    backwards ();
    endgo();
    left ();
   }
else {
  endgo();
   backwards ();
   endgo();
  right();
  }
   previoustimewheels = currrenttimewheels;
 }
  
}

 
void go () {
  
servoG.write(A) ;
servoD.write (B) ;

}

void endgo () {
if ( currrenttimewheels - previoustimewheels > waittimewheels) {
servoG.write (90) ;
servoD.write (90) ;

}
 }

void backwards () {
if ( currrenttimewheels - previoustimewheels > waittimewheels) {
servoG.write (B) ;
servoD.write (A) ;

}
 }

void left () {
if ( currrenttimewheels - previoustimewheels > waittimewheels) {
servoG.write (B) ;
servoD.write (B) ;

}
 }

void right () {
if ( currrenttimewheels - previoustimewheels > waittimewheels) {
servoG.write (A) ;
servoD.write (A) ;

}
 }

and secondly , how could i have his head pan while the robot is still moving. as if I would like him to never stop turning his head . even if the robot is stopping. moving forward/backwards/left/right. ?

thanks a lot for your help

2

TIP:

the IDE has the CTRL-T implemented to re-indent code to make it better readable.

if ( uS60 + uS40 > uS120 + uS140 ) {

are dangerous without enough ()

if ( (uS60 + uS40) > (uS120 + uS140) ) {

is more robust

TO get rid of the delay's you must introduce a state variable to reflect the current activity
and use the blink without delay technique. to change it at the right moment.

3

Hi ok thanks for the tip.

As you can see in my seconde code. I tried to implement the blink without delay code.
But I must have done something wrong. it doesn"t work.
the robot only goes forward. never stops. and turns it's head... that all.
It won't stop. won't go backwards or turn...

4

The demo several things at a time illustrates how to use millis() to manage timing.

...R