How to Connect an Output Value to an Output PIN

Development Boards Arduino
1

Hi there,

I have made a person counter,

Here is the code:

#define trigPin1 6

#define echoPin1 7

#define trigPin2 8

#define echoPin2 12

int hit1 = 0, hit2 = 0;

int numEntries = 0, numExits = 0;

// include the library code:

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins

LiquidCrystal lcd(11,10,9,2,3,4,5);

void setup() {

Serial.begin(9600);

// set up the LCD’s number of columns and rows:

lcd.begin(16, 2);

//Print a message to the LCD.

lcd.print(“Persons:”);

//sensors

pinMode(trigPin1, OUTPUT);

pinMode(echoPin1, INPUT);

pinMode(trigPin2, OUTPUT);

pinMode(echoPin2, INPUT);

}

void loop() {

// set the cursor to column 0, line 1

lcd.setCursor(0, 1);

//check sensor1

int duration, distance;

digitalWrite(trigPin1, LOW);

delayMicroseconds (2);

digitalWrite (trigPin1, HIGH);

delayMicroseconds (5);

digitalWrite (trigPin1, LOW);

duration = pulseIn (echoPin1, HIGH);

distance = (duration/2) / 29.1;

if(distance < 50){

Serial.println(“Entering…”);

hit1 = 1;

}

//check sensor2

int duration2, distance2;

digitalWrite(trigPin2, LOW);

delayMicroseconds (2);

digitalWrite (trigPin2, HIGH);

delayMicroseconds (5);

digitalWrite (trigPin2, LOW);

duration2 = pulseIn (echoPin2, HIGH);

distance2 = (duration2 / 2) / 29.1;

if(distance2 < 50){

Serial.println(“Exitting…”);

hit2 = 1;

}

//entry was triggered, scan exit until exit is hit

while(hit1 == 1 && hit2 == 0){

//check sensor2

int dur, dist;

digitalWrite(trigPin2, LOW);

delayMicroseconds (2);

digitalWrite (trigPin2, HIGH);

delayMicroseconds (5);

digitalWrite (trigPin2, LOW);

dur = pulseIn (echoPin2, HIGH);

dist = (dur / 2) / 29.1;

if(dist < 50){

//reset the two values

hit1 = 0;

hit2 = 0;

numEntries++;

Serial.println(“\tENTERED”);

break;

}

}

//exit was triggered, scan entry until entry is hit

while(hit1 == 0 && hit2 == 1){

//check sensor2

int dur, dist;

digitalWrite(trigPin1, LOW);

delayMicroseconds (2);

digitalWrite (trigPin1, HIGH);

delayMicroseconds (5);

digitalWrite (trigPin1, LOW);

dur = pulseIn (echoPin1, HIGH);

dist = (dur / 2) / 29.1;

if(dist < 50){

//reset the two values

hit1 = 0;

hit2 = 0;

numExits++;

Serial.println(“\tEXITED”);

delay(100);

break;

}

}

/* DEBUGGING

Serial.print(distance);

Serial.print(“-----”);

Serial.print(distance2);

Serial.println();

*/

// print the number of seconds since reset:

lcd.print(numEntries - numExits);

delay(100);

}

I have one pin left on my Arduino Uno - Pin 13. I want to edit that code to make Pin 13 Output LOW when value of the LCD count “persons” is 0 and Pin 13 Output be HIGH when the result is greater than 0.

Can anyone help me?

Thanks,

Ardalan G.

2

Please use Code Tags (from the Full Editor) around your code so it will read properly.

You are using two blocking methods in you code that will cause problems.

  • while() will remain in that while loop until conditions are satisfied - no other code will run until it exits the loop.

  • pulsein() will wait (forever, I think) until the input is received. pulsein(pin, value, timeout) will expire upon timeout but still blocks all other code.

But, back to your question, setup the pin_13 in setup(), resolve your numEntries and numExits to a variable (maybe numPersons) or just do the math at the if() test and then something along these lines (put this inside your loop:

if (numPersons >0)
 	{
	digitalWrite(pin13, HIGH)
	}
else
 	{
	digitalWrite(pin13, LOW)
	}

you should look into non-blocking code.

search for BlinkWithoutDelay and that’ll get you started.

3

Thank You!!