HC-SR04 SENSOR continuously out putting on number

Projects Programming
1

Im doing a school project, where we make a robot that is supposed to be able to find its way around a room. We have run into a wall that we have been trying to climb for days with this sensor.

#include <Servo.h>
#include<AFMotor.h>



// Declare classes for Servo connectors of the MotorShield.
Servo servo_1;
Servo servo_2;



const int Trig = 8;
const int Echo = 10;
const int PWR = 6;
const int Close= 5; 
int distance;

AF_DCMotor MotorL(1);
AF_DCMotor MotorR(4);



void setup() {
    //start motors
     MotorL.setSpeed(200);
     MotorL.run(RELEASE);
     MotorR.setSpeed(200);
     MotorL.run(RELEASE);
  
    pinMode(Trig, OUTPUT);
    pinMode(Echo, INPUT);
    pinMode(0, OUTPUT);

    Serial.begin(9600);

}

void loop() {
  delay(1000);
  digitalWrite(PWR, HIGH);
  Think();
 
 
}



void Think(){
  int turn;
  int D = Get_Distance();
  if (D >= Close){
   turn = random(1,2);
   if (turn == 1){
     MotorL.run(RELEASE);
     MotorL.run(FORWARD);
     MotorR.run(RELEASE);
     MotorR.run(BACKWARD);
     //motor right backward
   }
  
   else if(turn == 2){
      MotorL.run(RELEASE);
      MotorL.run(BACKWARD);
      MotorR.run(RELEASE);
      MotorR.run(FORWARD);
     //motor left forward
    }
  }
  else if (D <= Close|| D == 0){
    MotorL.run(RELEASE);
      MotorL.run(FORWARD);
      MotorR.run(RELEASE);
      MotorR.run(FORWARD);
    //motor left forward
    //motor left backward
 }
}

int Get_Distance(){
  long duration;
    digitalWrite(Trig, LOW);
    delayMicroseconds(2);
    digitalWrite(Trig, HIGH);
    delayMicroseconds(10);
    digitalWrite(Trig, LOW);
    duration = pulseIn(Echo, HIGH);
    delayMicroseconds(10);
    distance = duration*0.034/2;
    Serial.begin(9600);
    Serial.print(distance);
    Serial.print("\n");

    return(distance);
}

the serial monitor is only out putting either 0 or 59, but mostly 59

2 
   turn = random(1,2);
   if (turn == 1){

This function will return all values greater than or equal to 1 that are less than 2. How many numbers fall in that range?

You might as well have:

   turn = 1;
   if(turn == 1) // Well, duh...
   {

    Serial.begin(9600);

This belongs in setup(), where it will be done ONCE, not every time you want to output data.

3

Try also printing "duration" and see what values that has.

Steve

4

Sorry for late reply and I did the suggested, this is what has happened

#include <Servo.h>
#include<AFMotor.h>



// Declare classes for Servo connectors of the MotorShield.
Servo servo_1;
Servo servo_2;


/*
Adding AI
Adding ultrasonic sensors
*/

const int Trig = 8;
const int Echo = 10;
const int Close= 10; 
int distance;



void setup() {
    pinMode(Trig, OUTPUT);
    pinMode(Echo, INPUT);
    pinMode(0, OUTPUT);

    Serial.begin(9600);

}

void loop() {

Get_Distance();
Think();
 
 
}



void Think(){
  int turn;
  if (distance >= Close){
   turn = random(0,3);
   if (turn == 1){
     //motor left forward
     //motor right backward
   }
  } 
   else if(turn == 2){
     //realse motors
     //motor left backward
     //motor left forward
    }
  else if (distance <= Close|| distance == 0){
    
    //motor left forward
    //motor left backward
 }
}

int Get_Distance(){
  long duration;
    digitalWrite(Trig, LOW);
    delayMicroseconds(2);
    digitalWrite(Trig, HIGH);
    delayMicroseconds(10);
    digitalWrite(Trig, LOW);
    duration = pulseIn(Echo, HIGH);
    distance = duration*0.034/2;
    Serial.print("dist:");
    Serial.print(distance);
    Serial.print("\n");
    Serial.print("duration:");
    Serial.print(duration);
    Serial.print("\n");
    return(distance);
}

dist:9
duration:544
dist:8
duration:525
dist:10
duration:645
dist:3875
duration:227965
dist:145
duration:8551
dist:3856
duration:226867
dist:141
duration:8309
dist:145
duration:8586
dist:143
duration:8418
dist:131
duration:7723
dist:24
duration:1446
dist:21
duration:1237
dist:10
duration:619
dist:11
duration:660
dist:10
duration:641
dist:11
duration:662
dist:11
duration:686
dist:11
duration:680
dist:11
duration:693
dist:11
duration:684
dist:11
duration:652
dist:10
duration:599
dist:9
duration:578
dist:9
duration:583
dist:10
duration:596
dist:3833
duration:225490
dist:0
duration:0
dist:0
duration:0
dist:3857
duration:226909
dist:3847
duration:226322
dist:3889
duration:228797
dist:142
duration:8401
dist:3881
duration:228319
dist:144
duration:8512
dist:3861
duration:227145
dist:0
duration:0
5 
#include <Servo.h>
#include<AFMotor.h>



// Declare classes for Servo connectors of the MotorShield.
Servo servo_1;
Servo servo_2;


/*
Adding AI
Adding ultrasonic sensors
*/

const int Trig = 8;
const int Echo = 10;
const int Close= 10; 
int distance;
AF_DCMotor MotorL(1);
AF_DCMotor MotorR(4);


void setup() {
    pinMode(Trig, OUTPUT);
    pinMode(Echo, INPUT);
    pinMode(0, OUTPUT);
    Serial.begin(9600);
}

void loop() {
Get_Distance();
Think();
}

int Get_Distance(){
  long duration;
    digitalWrite(Trig, LOW);
    delayMicroseconds(2);
    digitalWrite(Trig, HIGH);
    delayMicroseconds(10);
    digitalWrite(Trig, LOW);
    duration = pulseIn(Echo, HIGH);
    distance = duration*0.034/2;
    Serial.print("dist:");
    Serial.print(distance);
    Serial.print("\n");
    Serial.print("duration:");
    Serial.print(duration);
    Serial.print("\n");
    return(distance);
}

void Think(){
  int turn;
  if (distance >= Close){
   turn = random(1,2);
   if (turn == 1){
     MotorL.run(RELEASE);
     MotorL.run(FORWARD);
     MotorR.run(RELEASE);
     MotorR.run(BACKWARD);
   }
   else if(turn == 2){
      MotorL.run(RELEASE);
      MotorL.run(BACKWARD);
      MotorR.run(RELEASE);
      MotorR.run(FORWARD);
    }
  }
  else if (distance <= Close|| distance == 0){
      MotorL.run(RELEASE);
      MotorL.run(FORWARD);
      MotorR.run(RELEASE);
      MotorR.run(FORWARD);
 }
}

dist:0
duration:0
dist:0
duration:0
dist:0
duration:0
dist:0
duration:0
dist:0
duration:0
dist:0
duration:0
dist:0
duration:0
dist:0

Update...

6

I'm not sure why you have any code to use distance when you are having problems getting distance.

I don't see any differences between the code that was outputting somewhat reasonable data and the code that is outputting all 0's. That suggests that you have a hardware problem.

Why does the Get_Distance() function return the value in a global variable?

Why does it return anything, when you don't care what the returned value is?