PIR Sensor Software Issues

Projects General Guidance
1

Hi,
I am using a pir (3 pin PIR) in my project and somehow the PIR is not responding. It doesn't detect motion. I tried the PIR with a simple code that turns an LED when motion is detected and it worked fine on the same pin i am using (i.e. Pin 9) however when I upload the code below the pir doesn't work. I hope someone could help me figure out the problem. I think the issue is purely software issue.
Code:

#include <Keypad.h>
const byte ROWS = 2;
const byte COLS = 2;
char keys[ROWS][COLS] =
{
  {
    '1','3'  }
  ,
  {
    '7','9'  }
  ,
};

byte rowPins [ROWS] = {
  5,6};
byte colPins [COLS] = {
  7,8};
Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );


int pirPin = 9;
int dataPin1 = 13;     //Name Pin. Define which pins will be used for the Shift Register control
int dataPin2 = 10;     //Off Pin
int dataPin3 = 11;    //CVN Pin
int dataPin4 = 12;    //Vacation Pin
int dataPin5 = 2;    //Here Pin
int latchPin = 3;
int clockPin = 4;
int val = 0;

int seq[14] = {
  1,2,4,8,16,32,64,128,64,32,16,8,4,2};       //The byte sequence



void setup()
{
  Serial.begin (9600); 
  pinMode(dataPin1, OUTPUT);
  pinMode(dataPin2, OUTPUT);
  pinMode(dataPin3, OUTPUT);
  pinMode(dataPin4, OUTPUT);
  pinMode(dataPin5, OUTPUT);     
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(pirPin, INPUT);
}




void handleKeypress (const char key)
{
  Serial.println (key);
}



void loop()

{

  for (int n = 0; n < 14; n++)
  {
    digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
    shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
    digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
    delay(20);
  }


  byte key = kpd.getKey();
  if (key)
    handleKeypress (key);

  val = digitalRead(pirPin);

  switch (key) {
  case '1':
//  Serial.println("entering loop");
    while(HIGH == val)
    {
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(20);
      }
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin2, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(50);
      }

    }
//Serial.println("exiting loop");
    break;
Serial.println("after break");
  case '3':
    while(HIGH == val)
    {
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(20);
      }
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin3, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(50);
      }

    }


    break;

  case '7':
    while(HIGH == val)
    {
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(20);
      }
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin4, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(50);
      }

    }


    break;

  case '9':
    while(HIGH == val)
    {
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(20);
      }
      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin5, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(50);
      }

    }


    break;

  }

}

Here is the code that I am using for the PIR you can find it scattered in the code above. I just copied it here below so you see what I am doing:

Code:

int pirPin = 9;
int val = 0;
pinMode(pirPin, INPUT);
val = digitalRead(pirPin);
 while(HIGH == val)

Thank you very much

Moderator edit:
</mark> <mark>[code]</mark> <mark>

</mark> <mark>[/code]</mark> <mark>
tags added.

2

for the readability of the code you should put

      for (int n = 0; n < 14; n++)
      {
        digitalWrite(latchPin, LOW);             //Pull latch LOW to start sending data
        shiftOut(dataPin1, clockPin, MSBFIRST, seq[n]);          //Send the data
        digitalWrite(latchPin, HIGH);            //Pull latch HIGH to stop sending data
        delay(20);
      }

in a separate function as this block of code repeats and repeats ...

3

Yes I agree with you. It's proper to put it in a separate function, but that's not the problem I have. The code will still work if I fix the PIR issues.

4

Still, encapsulating code in (verified) functions will give you focus on where the failing part of the code can be as that will be "hidden" in less lines of code.

If you made it a function you would see that the for loop uses delay()
That function would have:

  • 14 times 50 milliseconds = 700 milliseconds blocking code
  • 14 times 20 milliseconds = 280 milliseconds blocking code
    That means to shift out the data you want you "block" the code for about a second.

That means the PIR sensor (and keyboard) is only read once per second. That can look as if the sensor is non reactive.

add these lines to show how often you read the sensor.

  val = digitalRead(pirPin);  // existing code
  // add this time stamped sensor value
  Serial.print(millis);
  Serial.print("\t");
  Serial/println(val, DEC);