7 Segment LED display Interfacing....

Here i will show you how to interface a 7 segment LED display with GR-Sakura (Arduino UNO compatible).

I have used LT543 Common Cathode display. Common Cathode LED’s (around Rs.10) are cheaper than Common Anode (around Rs.30).

 

Circuit Diagram:

The resistors i used are of 1k ohm. 3^rd and 8^th pin goes to ground.

CountDown from 9 to 0:

 

Code:

#include<rxduino.h>

byte seven[12][7] = { { 1,1,1,1,1,1,0 },  // = 0

                        { 0,1,1,0,0,0,0 },  // = 1

                      { 1,1,0,1,1,0,1 },  // = 2

                      { 1,1,1,1,0,0,1 },  // = 3

                      { 0,1,1,0,0,1,1 },  // = 4

                      { 1,0,1,1,0,1,1 },  // = 5

                      { 1,0,1,1,1,1,1 },  // = 6

                      { 1,1,1,0,0,0,0 },  // = 7

                      { 1,1,1,1,1,1,1 },  // = 8

                      { 1,1,1,1,0,1,1 },  // = 9

                     };

int pins[10]={30,31,32,33,7,6,5,4};

int main()

{               

  static int i=9,j;

  pinMode(30, OUTPUT);  

  pinMode(31, OUTPUT);

  pinMode(32, OUTPUT);

  pinMode(33, OUTPUT);

  pinMode(6, OUTPUT);

  pinMode(7, OUTPUT);

  pinMode(5, OUTPUT);

  pinMode(4, OUTPUT);

 

  delay(100);

  digitalWrite(4,1);

  while(1)

  {

                                  if(i<0)

                                  {

                                                  i=9;

                                  }

                                  else

                                  {

                                  for(j=0;j<7;j++)

                                  {

                                                  digitalWrite(pins[j],seven[i][j]);

                                  }

                                  delay(1000);

                                  i--;

                                  }

                  }

} 

 

Interfacing with Keys to control the displaying count value:

 

Code:
 

#include<rxduino.h>

byte seven[20][7] = { { 1,1,1,1,1,1,0 },  // = 0

                      { 0,1,1,0,0,0,0 },  // = 1

                      { 1,1,0,1,1,0,1 },  // = 2

                      { 1,1,1,1,0,0,1 },  // = 3

                      { 0,1,1,0,0,1,1 },  // = 4

                      { 1,0,1,1,0,1,1 },  // = 5

                      { 1,0,1,1,1,1,1 },  // = 6

                      { 1,1,1,0,0,0,0 },  // = 7

                      { 1,1,1,1,1,1,1 },  // = 8

                      { 1,1,1,1,0,1,1 },  // = 9

                      { 1,1,1,0,1,1,1 },  // = A

                      { 1,1,1,1,1,1,1 },  // = B

                      { 1,0,0,1,1,1,0 },  // = C

                      { 1,1,1,1,1,1,0 },  // = D

                      { 1,0,0,1,1,1,1 },  // = E

                      { 1,0,0,0,1,1,1 }   // = F

                     };

int pins[10]={30,31,32,33,7,6,5,4};

 

int main()

{               

  static int i=-1,j;

  pinMode(30, OUTPUT);  

  pinMode(31, OUTPUT);

  pinMode(32, OUTPUT);

  pinMode(33, OUTPUT);

  pinMode(6, OUTPUT);

  pinMode(7, OUTPUT);

  pinMode(5, OUTPUT);

  pinMode(4, OUTPUT);

  pinMode(34, INPUT);   // input for key (increasing count)

  pinMode(35, INPUT);   // input for key (decreasing count)

  delay(100);

  digitalWrite(4,1);

  while(1)

  {

  if(digitalRead(34)==0)

  {

                  delay(200);        // Switch debouncing delay

                  if(digitalRead(34)==0)

                  {

                                  i++;

                                  if(i<16)                                                 

                                                {

                                                for(j=0;j<7;j++)

                                                {

                                                  delay(10);

                                                  digitalWrite(pins[j],seven[i][j]);

                                                }

                                                }

                                                else

                                                {

                                                                i=16;

                                                }

                  }

  }

   if(digitalRead(35)==0)

  {

                  delay(200);       // Switch debouncing delay

                  if(digitalRead(35)==0)

                  {

                                  if(i<0)

                                  {

                                                  i=0;

                                  }

                                  else

                                  {

                                  delay(10);

                                  for(j=0;j<7;j++)

                                  {

                                                  digitalWrite(pins[j],seven[i][j]);

                                  }

                                  i--;

                                  }

                  }

  }

  }

}

 

Video Demo: