Help with Motor DC + Ultrassonic

Using Arduino Programming Questions
1

Hello guys,

I´m trying to make a program with two DC motors and an ultrassonic sensor. in an arduino UNO. It´s really basic, if the sensor pick up a distance below 10cm, the motors must stop. But it doesn´t happen. The DC motors function normally and the sensor show the distance correctly, but the motors does´t stop when reach distance below 10cm. Follow the code:

 const int Trig = 7;
const int Echo = 8;

int cm;

int IN1 = 3;
int IN2 = 4;
int IN3 = 5;
int IN4 = 6;

void setup()
{
  Serial.begin(9600); 

  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
  
  pinMode(Trig, OUTPUT);
  pinMode(Echo, INPUT);

}

void loop()
{
  //TURN ON THE MOTOR A
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);

  //TURN ON TH MOTOR B
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
 
  //SENSOR ULTRASSONIC
  digitalWrite(Trig, LOW);       
  delayMicroseconds(2);
  digitalWrite(Trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(Trig, LOW);
  cm = pulseIn(Echo, HIGH) / 58.0; //The echo time is converted into cm
  cm = (int(cm * 100.0)) / 100.0;     //Keep two decimal places
  Serial.println(cm);
 

  if(cm<10)
 { 
      
      //STOP THE MOTOR A
      digitalWrite(IN1, LOW);
      
      //STOP THE MOTOR B
      digitalWrite(IN3, LOW);

 }
}

Please, somebody could help me with this code? This is the components that I´m using:

1412×1056 58 KB

Thanks in advance,
Henry

2

You are stopping the motor .... for about ten microseconds.

3

Hello @AWOL thank you for your reply!
How do you come to that conclusion? Do you what should I do to make it happen only when the sensor reach distance below to 10cm?

Thank you,
Henry

4

Because the loop function repeats, shortly after you stop the motors, you start them again.

5

Thank you. About this, how could I keep the comand "if" in function in order to stop the motors while the distance is below the distance of 10cm?

6

You could start the motors in setup(), and stop them in loop(), possibly restarting them in an else clause.