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JRobert
JRobert
  • 15.4k
  • 3
  • 25
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int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
   Serial.begin(9600);
   for(i=0;i<=3;i++)
   {
      pinMode(row[i],OUTPUT);
      pinMode(col[i],INPUT);
      digitalWrite(col[i],HIGH);
   } }
void loop()
{ 
   for(i=0; i<=3; i++)
   {
      digitalWrite(row[0],HIGH);
      digitalWrite(row[1],HIGH);
      digitalWrite(row[2],HIGH);
      digitalWrite(row[3],HIGH);
      digitalWrite(row[i],LOW);
      for(j=0; j<=3; j++)
      {
     col_scan=digitalRead(col[j]);
     if(col_scan==LOW)
     {
        keypress(i,j);
        delay(300);
     }}
   }}
void keypress(int i, int j)
{
   if(i==0&&j==0)
      Serial.println("1");
   if(i==0&&j==1)
      Serial.println("2");
   if(i==0&&j==2)
      Serial.println("3");
   if(i==0&&j==3)
      Serial.println("A");
   if(i==1&&j==0)
      Serial.println("4");
   if(i==1&&j==1)
      Serial.println("5");
   if(i==1&&j==2)
      Serial.println("6");
   if(i==1&&j==3)
      Serial.println("B");
   if(i==2&&j==0)
      Serial.println("7");
   if(i==2&&j==1)
      Serial.println("8");
   if(i==2&&j==2)
      Serial.println("9");
   if(i==2&&j==3)
      Serial.println("C");
   if(i==3&&j==0)
      Serial.println("*");
   if(i==3&&j==1)
      Serial.println("0");
   if(i==3&&j==2)
      Serial.println("#");
   if(i==3&&j==3)
      Serial.println("D");
}

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
   Serial.begin(9600);
   for(i=0;i<=3;i++)
   {
      pinMode(row[i],OUTPUT);
      pinMode(col[i],INPUT);
      digitalWrite(col[i],LOW);
   } }
void loop()
{ 
   for(i=0; i<=3; i++)
   {
      digitalWrite(row[0],LOW);
      digitalWrite(row[1],LOW);
      digitalWrite(row[2],LOW);
      digitalWrite(row[3],LOW);
      digitalWrite(row[i],HIGH);
      for(j=0; j<=3; j++)
      {
     col_scan=digitalRead(col[j]);
     if(col_scan==HIGH)
     {
        keypress(i,j);
        delay(300);
     }}
   }}
void keypress(int i, int j)
{
   if(i==0&&j==0)
      Serial.println("1");
   if(i==0&&j==1)
      Serial.println("2");
   if(i==0&&j==2)
      Serial.println("3");
   if(i==0&&j==3)
      Serial.println("A");
   if(i==1&&j==0)
      Serial.println("4");
   if(i==1&&j==1)
      Serial.println("5");
   if(i==1&&j==2)
      Serial.println("6");
   if(i==1&&j==3)
      Serial.println("B");
   if(i==2&&j==0)
      Serial.println("7");
   if(i==2&&j==1)
      Serial.println("8");
   if(i==2&&j==2)
      Serial.println("9");
   if(i==2&&j==3)
      Serial.println("C");
   if(i==3&&j==0)
      Serial.println("*");
   if(i==3&&j==1)
      Serial.println("0");
   if(i==3&&j==2)
      Serial.println("#");
   if(i==3&&j==3)
      Serial.println("D");
}

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],HIGH);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],HIGH);
digitalWrite(row[1],HIGH);
digitalWrite(row[2],HIGH);
digitalWrite(row[3],HIGH);
digitalWrite(row[i],LOW);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==LOW)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],LOW);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],LOW);
digitalWrite(row[1],LOW);
digitalWrite(row[2],LOW);
digitalWrite(row[3],LOW);
digitalWrite(row[i],HIGH);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==HIGH)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
   Serial.begin(9600);
   for(i=0;i<=3;i++)
   {
      pinMode(row[i],OUTPUT);
      pinMode(col[i],INPUT);
      digitalWrite(col[i],HIGH);
   } }
void loop()
{ 
   for(i=0; i<=3; i++)
   {
      digitalWrite(row[0],HIGH);
      digitalWrite(row[1],HIGH);
      digitalWrite(row[2],HIGH);
      digitalWrite(row[3],HIGH);
      digitalWrite(row[i],LOW);
      for(j=0; j<=3; j++)
      {
     col_scan=digitalRead(col[j]);
     if(col_scan==LOW)
     {
        keypress(i,j);
        delay(300);
     }}
   }}
void keypress(int i, int j)
{
   if(i==0&&j==0)
      Serial.println("1");
   if(i==0&&j==1)
      Serial.println("2");
   if(i==0&&j==2)
      Serial.println("3");
   if(i==0&&j==3)
      Serial.println("A");
   if(i==1&&j==0)
      Serial.println("4");
   if(i==1&&j==1)
      Serial.println("5");
   if(i==1&&j==2)
      Serial.println("6");
   if(i==1&&j==3)
      Serial.println("B");
   if(i==2&&j==0)
      Serial.println("7");
   if(i==2&&j==1)
      Serial.println("8");
   if(i==2&&j==2)
      Serial.println("9");
   if(i==2&&j==3)
      Serial.println("C");
   if(i==3&&j==0)
      Serial.println("*");
   if(i==3&&j==1)
      Serial.println("0");
   if(i==3&&j==2)
      Serial.println("#");
   if(i==3&&j==3)
      Serial.println("D");
}

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
   Serial.begin(9600);
   for(i=0;i<=3;i++)
   {
      pinMode(row[i],OUTPUT);
      pinMode(col[i],INPUT);
      digitalWrite(col[i],LOW);
   } }
void loop()
{ 
   for(i=0; i<=3; i++)
   {
      digitalWrite(row[0],LOW);
      digitalWrite(row[1],LOW);
      digitalWrite(row[2],LOW);
      digitalWrite(row[3],LOW);
      digitalWrite(row[i],HIGH);
      for(j=0; j<=3; j++)
      {
     col_scan=digitalRead(col[j]);
     if(col_scan==HIGH)
     {
        keypress(i,j);
        delay(300);
     }}
   }}
void keypress(int i, int j)
{
   if(i==0&&j==0)
      Serial.println("1");
   if(i==0&&j==1)
      Serial.println("2");
   if(i==0&&j==2)
      Serial.println("3");
   if(i==0&&j==3)
      Serial.println("A");
   if(i==1&&j==0)
      Serial.println("4");
   if(i==1&&j==1)
      Serial.println("5");
   if(i==1&&j==2)
      Serial.println("6");
   if(i==1&&j==3)
      Serial.println("B");
   if(i==2&&j==0)
      Serial.println("7");
   if(i==2&&j==1)
      Serial.println("8");
   if(i==2&&j==2)
      Serial.println("9");
   if(i==2&&j==3)
      Serial.println("C");
   if(i==3&&j==0)
      Serial.println("*");
   if(i==3&&j==1)
      Serial.println("0");
   if(i==3&&j==2)
      Serial.println("#");
   if(i==3&&j==3)
      Serial.println("D");
}
added 2906 characters in body
Source Link
Samdish Arora
Samdish Arora
  • 63
  • 1
  • 4

The code that works:-

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],HIGH);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],HIGH);
digitalWrite(row[1],HIGH);
digitalWrite(row[2],HIGH);
digitalWrite(row[3],HIGH);
digitalWrite(row[i],LOW);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==LOW)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}

the code that doesn't work:-

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],LOW);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],LOW);
digitalWrite(row[1],LOW);
digitalWrite(row[2],LOW);
digitalWrite(row[3],LOW);
digitalWrite(row[i],HIGH);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==HIGH)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}

The code that works:-

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],HIGH);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],HIGH);
digitalWrite(row[1],HIGH);
digitalWrite(row[2],HIGH);
digitalWrite(row[3],HIGH);
digitalWrite(row[i],LOW);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==LOW)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}

the code that doesn't work:-

int row[]={6,7,8,9};
int col[]={10,11,12,13};
int i,j; 
int col_scan;
void setup()
{
 Serial.begin(9600);
 for(i=0;i<=3;i++)
{
pinMode(row[i],OUTPUT);
pinMode(col[i],INPUT);
digitalWrite(col[i],LOW);
} }
void loop()
{ 
for(i=0; i<=3; i++)
{
digitalWrite(row[0],LOW);
digitalWrite(row[1],LOW);
digitalWrite(row[2],LOW);
digitalWrite(row[3],LOW);
digitalWrite(row[i],HIGH);
for(j=0; j<=3; j++)
{
col_scan=digitalRead(col[j]);
if(col_scan==HIGH)
{
keypress(i,j);
delay(300);
}}
}}
void keypress(int i, int j)
{
if(i==0&&j==0)
Serial.println("1");
if(i==0&&j==1)
Serial.println("2");
if(i==0&&j==2)
Serial.println("3");
if(i==0&&j==3)
Serial.println("A");
if(i==1&&j==0)
Serial.println("4");
if(i==1&&j==1)
Serial.println("5");
if(i==1&&j==2)
Serial.println("6");
if(i==1&&j==3)
Serial.println("B");
if(i==2&&j==0)
Serial.println("7");
if(i==2&&j==1)
Serial.println("8");
if(i==2&&j==2)
Serial.println("9");
if(i==2&&j==3)
Serial.println("C");
if(i==3&&j==0)
Serial.println("*");
if(i==3&&j==1)
 Serial.println("0");
if(i==3&&j==2)
Serial.println("#");
if(i==3&&j==3)
Serial.println("D");
}
Source Link
Samdish Arora
Samdish Arora
  • 63
  • 1
  • 4

Interfacing Hex keypad with arduino

I was trying to interface my hex keypad with Arduino. I declared rows as input and columns as output. When I initialize three of the four columns as HIGH and one as LOW, and detect the button pressed as LOW in the corresponding row, it works fine. That is, it detects the button when its corresponding row and column is LOW. But, when I reverse the condition, i.e. when I try to detect the button pressed when its corresponding row and column is high while others are low, it does not work as expected.

I really want to know why is this happening?