Arduino 7 Segment LED Display and Counter

Arduino 7 Segment LED Display and Counter

This is a simple 0 to 9 counter circuit constructed using Arduino! Here, a common cathode 7-segment LED display is connected to Arduino for displaying the digits.
The whole circuit can be powered from a standard 9V PP3/6F22 battery, or from any suitable Arduino power adaptor.

The seven segment display is infact a very simple device. It is a combination of 8 LEDs (the decimal point -DP- is the 8th), which can be arranged so that different combinations can be used to make numerical digits.

Details of a common cathode type 7 segment LED display is shown here. Note that pins 3 and 8 of the display is the cathode terminals.

Just follow the schematic circuit diagram to make the entire project.
Arduino pins 2, 3, 4, 5, 6, 7 and 8 should go to Display pins 7, 6, 4, 2, 1, 9 and 10 in correct order. In case of any doubt refer this table.

Connecting the display pins directly to Arduino I/O pins is not a good practice. For testing purpose only one 330 Ohm resistor (R2) is added between ground rail (0V) and the common cathode pins (3 & 8). It is better to directly connect pins 3 & 8 of the display to ground rail. Next add a 330 Ohm resistor between each of the other connections to the Arduino.

Programming

int pausa=1000; 

void setup()

{

  pinMode(2, OUTPUT);  

  pinMode(3, OUTPUT);

  pinMode(4, OUTPUT);

  pinMode(5, OUTPUT);

  pinMode(6, OUTPUT);

  pinMode(7, OUTPUT);

  pinMode(8, OUTPUT);

}

void display (int a, int b, int c, int d, int e, int f, intg)

{

  digitalWrite (2,a);   

  digitalWrite (3,b);   

  digitalWrite (4,c);

  digitalWrite (5,d);

  digitalWrite (6,e);

  digitalWrite (7,f);

  digitalWrite (8,g);

}

void loop() 

{

  display (1,1,1,1,1,1,0); //write 0

  delay(pausa);

  display (0,1,1,0,0,0,0); //write 1

  delay(pausa);

  display (1,1,0,1,1,0,1); //write 2

  delay(pausa);

  display (1,1,1,1,0,0,1); //write 3

  delay(pausa);

  display (0,1,1,0,0,1,1); //write 4

  delay(pausa);

  display (1,0,1,1,0,1,1); //write 5

  delay(pausa);

  display (1,0,1,1,1,1,1); //write 6

  delay(pausa);

  display (1,1,1,0,0,0,0); //write 7

  delay(pausa);

  display (1,1,1,1,1,1,1); //write 8

  delay(pausa);

  display (1,1,1,0,0,1,1); //write 9

  delay(pausa);

}

Frank.