Declaration for a set of code.

Projects Programming
1

I was wondering if it was possible to give a chunk of code(specifically a chunk of code to run ultrasonic sensors), a name and declare it as a variable.

here is my code:

#define trigPin1 11
#define echoPin1 12

long duration, distance, RightSensor,BackSensor,FrontSensor,LeftSensor;

void setup()
{
Serial.begin (9600);
pinMode(trigPin1, OUTPUT);
pinMode(echoPin1, INPUT);
SonarSensor(trigPin1, echoPin1);
RightSensor = distance;
int SensVala = Serial.println(RightSensor);
}

void SonarSensor(int trigPin,int echoPin)
{
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance = (duration/2) / 29.1;

}

void loop() {

}

3

Please edit your post and use code tags for the code

Type
** **[code]** **
before the code
Type
** **[/code]** **
after the code

I think what you want is a function that returns a value. Looking at this

void SonarSensor(int trigPin, int echoPin)
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1;
}

you're only interested in the distance. You're function can return the distance.

/*
  read sonar distance
  input:
    trigger pin
    echo pin
  returns:
    distance in cm
*/
long SonarSensor(int trigPin, int echoPin)
{
  ...
  ...

Next you can do the calculation as you did

/*
  read sonar distance
  returns:
    distance in cm
*/
long SonarSensor(int trigPin, int echoPin)
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1;

  // return measured distance
  return distance;
}

And in e.g. loop()

void loop()
{
  // get the distance
  RightSensor = SonarSensor(trigPin1, echoPin1);

  Serial.print("distance = "); Seral.println(RightSensor);
}

Now I would clean the function up a little. Nowhere in your code you will be interested in the duration. So instead of making that a global variable, you can declare it inside the function (local variable).

long SonarSensor(int trigPin, int echoPin)
{
  // variable to hold measured duration
  long duration;
   
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1;

  // return measured distance
  return distance;
}

And remove the duration from the global variables near the top of the code.

#define trigPin1 11
#define echoPin1 12

//WAS: long duration, distance, RightSensor, BackSensor, FrontSensor, LeftSensor;
long distance, RightSensor, BackSensor, FrontSensor, LeftSensor;

...
...

You can do the same for distance; I would make it a local variable in the SonarSensor function and get rid of it in the global section.

Note
At the moment that you start numbering variables (e.g. trigPin1), it's time to consider arrays.

4 
void SonarSensor(int trigPin, int echoPin)
{
  // variable to hold measured duration
  long duration;
   
  // return measured distance
  return distance;
}

Fail! void functions do not have return statements.

5

Thanks for the correction :slight_smile: Fixed it