7 Segment Display on Arduino

This instructable shows how to display 0-9 digits on 7 Segment Display using Arduino.

What do you need:

• Arduino Uno 3
• 7 Seven Segment Display
• 2 x 220 Ohm Resistors
• Jumper Wires

Step 1: Making Connections

Connect the pins described below:

1. Arduino Pin 2 to Pin 9.
2. Arduino Pin 3 to Pin 10.

3. Arduino Pin 4 to Pin 4.

4. Arduino Pin 5 to Pin 2..

5. Arduino Pin 6 to Pin 1.

6. Arduino Pin 8 to Pin 7.

7. Arduino Pin 9 to Pin 6.

8. GND to Pin 3 and Pin 8 each connected with 220 ohm resistors.

Step 2: Arduino Code

int a = 2;  //For displaying segment "a"

int b = 3;  //For displaying segment "b"
int c = 4;  //For displaying segment "c"
int d = 5;  //For displaying segment "d"
int e = 6;  //For displaying segment "e"
int f = 8;  //For displaying segment "f"
int g = 9;  //For displaying segment "g"

void setup() {               
  pinMode(a, OUTPUT);  //A
  pinMode(b, OUTPUT);  //B
  pinMode(c, OUTPUT);  //C
  pinMode(d, OUTPUT);  //D
  pinMode(e, OUTPUT);  //E
  pinMode(f, OUTPUT);  //F
  pinMode(g, OUTPUT);  //G
}

void displayDigit(int digit)
{
 //Conditions for displaying segment a
 if(digit!=1 && digit != 4)
 digitalWrite(a,HIGH);
 
 //Conditions for displaying segment b
 if(digit != 5 && digit != 6)
 digitalWrite(b,HIGH);
 
 //Conditions for displaying segment c
 if(digit !=2)
 digitalWrite(c,HIGH);
 
 //Conditions for displaying segment d
 if(digit != 1 && digit !=4 && digit !=7)
 digitalWrite(d,HIGH);
 
 //Conditions for displaying segment e 
 if(digit == 2 || digit ==6 || digit == 8 || digit==0)
 digitalWrite(e,HIGH);
 
 //Conditions for displaying segment f
 if(digit != 1 && digit !=2 && digit!=3 && digit !=7)
 digitalWrite(f,HIGH);
 if (digit!=0 && digit!=1 && digit !=7)
 digitalWrite(g,HIGH);
 
}
void turnOff()
{
  digitalWrite(a,LOW);
  digitalWrite(b,LOW);
  digitalWrite(c,LOW);
  digitalWrite(d,LOW);
  digitalWrite(e,LOW);
  digitalWrite(f,LOW);
  digitalWrite(g,LOW);
}


void loop() {

 for(int i=0;i<10;i++)
 {
   displayDigit(i);
   delay(1000);
   turnOff();
 }
}

Comments

[alitaha978779]

Connect 7-segments to Arduino board and write a program to show the following letters instead of numbers in the same sequence (O, A,C,E,F,H,I,L,P)

[okozlov7]

Here you can watch my version of 7 segment indicator project:
https://positiveknight.com/arduino-project-4-countdown-on-indicator/

[danmetz56]

Hi, the pins 3 and 8 are connected inside. So you need to connect the ground only once with one resistor 220ohms. If you connect the pins 3 and 8 with two resistors 220ohms you get 110ohms (parallel)

[shanedon1954]

Wow I stuggled for 2 hours.
Problem solved.
Suggest
1. change the GND to VCC
2. Replace all the HIGH to LOW and the LOW to HIGH in code.
3. Pin numbers must be :
Arduino : Display
2 : 7
3 : 6
4 : 4
5 : 2
6 : 1
8 : 9
9 : 10
Hope this helps
Regards
Shanedon

[Wasil Islam]

Thanks!
this helped a lot. I w a s thinking of giving up on Seven Seg Display ; )

[allesklusser]

Hello. For the first time here but did in the meanwhile a lot of small projects with clocks.
It seems that there is a fault with the pinlayout of the 7 seg single display. The pinnumbers from 1 to 5 are correct. The upper ones are reversed in the picture (not on the Fritzing picture). The correct upper pinnumbers are from left to right 6, 7, 8, 9, 10
Just now I saw that Shanedon made the correction. Maybe a good idea the correct the picture of the 7seg layout.

[alaahajba]

int a = 2;
int b = 3;
int c = 4;
int d = 5;
int e = 6;
int f = 9;
int g = 10;
void setup() {
pinMode(a, OUTPUT);
pinMode(b, OUTPUT);
pinMode(c, OUTPUT);
pinMode(d, OUTPUT);
pinMode(e, OUTPUT);
pinMode(f, OUTPUT);
pinMode(g, OUTPUT);
}
void displayDigit(int digit)
{
if(digit!=1 && digit != 4)
digitalWrite(f,HIGH);

if(digit != 5 && digit != 6)
digitalWrite(g,HIGH);

if(digit !=2)
digitalWrite(c,HIGH);

if(digit != 1 && digit !=4 && digit !=7)
digitalWrite(d,HIGH);

if(digit == 2 || digit ==6 || digit == 8 || digit==0)
digitalWrite(e,HIGH);

if(digit != 1 && digit !=2 && digit!=3 && digit !=7)
digitalWrite(a,HIGH);
if (digit!=0 && digit!=1 && digit !=7)
digitalWrite(b,HIGH);

}
void turnOff()
{
digitalWrite(a,LOW);
digitalWrite(b,LOW);
digitalWrite(c,LOW);
digitalWrite(d,LOW);
digitalWrite(e,LOW);
digitalWrite(f,LOW);
digitalWrite(g,LOW);
}


void loop() {
for(int i=0;i<10;i++)
{
displayDigit(i);
delay(1000);
turnOff();
}
}

[tcspratlin42]

What is the part number for the 7 seven segment display?

[The_314159265359_Fan]

5161AS

[GeirG1]

Thanks for nice instructions! Here is how I would code it:

const int numberPins[] = { 9, 8, 6, 5, 4, 3, 2 };
void setup() {
for(int i = 0; i < 7; i++)
pinMode(numberPins[i], OUTPUT);
turnOff();
}
void displayDigit(int digit)
{
static byte numbers[] = { 95, 18, 47, 59, 114, 121, 125, 19, 127, 123 };
byte mask = 1;
for(int pin = 0; pin < 7; pin++)
{
if(numbers[digit] & (1 << pin))
digitalWrite(numberPins[pin], HIGH);
else
digitalWrite(numberPins[pin], LOW);
mask = mask * 2;
}
}

void turnOff()
{
for(int i = 0; i < 7; i++)
digitalWrite(numberPins[i], LOW);
}

[a-sacramento]

If have two displays how I command the second display? Do you have a solution for that?

[AnaviD]

What's the ! mark after digit mean?

[saurav_hack]

It means if the digit is not equal to. ('!') means not in programming language.

[ScottyM10]

! is like saying not.

!= means 'not equal'

[ViduraM1]

its working great, better to configure the jumper wires as its in the fritzing diagram.

Thanks

[gajesh123]

How to run it?

[JaromírI]

This is an example only for "Common katode" , am i right?

[DarthV14]

Why resistors before GND?

[CHRISTO CJ]

to save the arduino pins from overload

[sbyas]

Doesn't work correctly. could you tell me why.