Led is very basic component in the design and some time led do lot more work than just indication.

In this article we will see how to build custom designed seven segment display using led.

There are lot of variety of seven segment in the market but i choose to build my own because of i had time and many leds laying around me.

I have used Kicad tool for schematic and PCB designing.

Here is the complete Guide:

Here is the code:

#define SEGMENT_A  5
#define SEGMENT_B 6
#define SEGMENT_C 7
#define SEGMENT_D 8
#define SEGMENT_E 9
#define SEGMENT_F 10
#define SEGMENT_G 11
//#define SEGMENT_dp  

#define SEG_SELECT_1  A3
#define SEG_SELECT_2  A2
#define SEG_SELECT_3  A1
#define SEG_SELECT_4  A0

#define SEGMENT_SWITCH_DELAY  5
int CounterPeriod = 1000;
unsigned long time_now = 0;
/*
    a
   --
  |  |
 f|g |b
   --
  |  |
 e|  |c
   --
   d
   
Byte = hgfedcba
*/
uint8_t segmentdecode[] = {0x3F,0x06,0x5B,0x4F,0x66,0x6D,0X7D,0X07,0X7f,0X6f,0X77,0x7C,0x39,0x5E,0x79,0x71};

void DisplayNum(uint8_t num)
{
    digitalWrite(SEGMENT_A, (num & 0x01)?HIGH:LOW);
    digitalWrite(SEGMENT_B, (num & 0x02)?HIGH:LOW);
    digitalWrite(SEGMENT_C, (num & 0x04)?HIGH:LOW);
    digitalWrite(SEGMENT_D, (num & 0x08)?HIGH:LOW);
    digitalWrite(SEGMENT_E, (num & 0x10)?HIGH:LOW);
    digitalWrite(SEGMENT_F, (num & 0x20)?HIGH:LOW);
    digitalWrite(SEGMENT_G, (num & 0x40)?HIGH:LOW);
}

void setup() {
  // put your setup code here, to run once:
    pinMode(LED_BUILTIN, OUTPUT);
    pinMode(SEGMENT_A, OUTPUT);

    pinMode(SEGMENT_A, OUTPUT);
    pinMode(SEGMENT_B, OUTPUT);
    pinMode(SEGMENT_C, OUTPUT);
    pinMode(SEGMENT_D, OUTPUT);
    pinMode(SEGMENT_E, OUTPUT);
    pinMode(SEGMENT_F, OUTPUT);
    pinMode(SEGMENT_G, OUTPUT);
//    pinMode(SEGMENT_dp,OUTPUT);

    pinMode(SEG_SELECT_1, OUTPUT);
    pinMode(SEG_SELECT_2, OUTPUT);
    pinMode(SEG_SELECT_3, OUTPUT);
    pinMode(SEG_SELECT_4, OUTPUT);
}

int i;
int Counter=0;
int convertedInUnit[4];
//1234
void DisplayOnSegment(int d)
{  
  convertedInUnit[0] = d/1000;
  digitalWrite(SEG_SELECT_1, HIGH);
  digitalWrite(SEG_SELECT_2, LOW);
  digitalWrite(SEG_SELECT_3, LOW);
  digitalWrite(SEG_SELECT_4, LOW);
  DisplayNum(segmentdecode[convertedInUnit[0]]);
  delay(SEGMENT_SWITCH_DELAY);
  DisplayNum(0x00);//1

  convertedInUnit[1] = (d%1000)/100;
  digitalWrite(SEG_SELECT_1, LOW);
  digitalWrite(SEG_SELECT_2, HIGH);
  digitalWrite(SEG_SELECT_3, LOW);
  digitalWrite(SEG_SELECT_4, LOW);
  DisplayNum(segmentdecode[convertedInUnit[1]]);
  delay(SEGMENT_SWITCH_DELAY);
  DisplayNum(0x00);//2

  convertedInUnit[2] = ((d%1000)%100)/10;
  digitalWrite(SEG_SELECT_1, LOW);
  digitalWrite(SEG_SELECT_2, LOW);
  digitalWrite(SEG_SELECT_3, HIGH);
  digitalWrite(SEG_SELECT_4, LOW);
  DisplayNum(segmentdecode[convertedInUnit[2]]);
  delay(SEGMENT_SWITCH_DELAY);
  DisplayNum(0x00);//3

  convertedInUnit[3] = ((d%1000)%100)%10;
  digitalWrite(SEG_SELECT_1, LOW);
  digitalWrite(SEG_SELECT_2, LOW);
  digitalWrite(SEG_SELECT_3, LOW);
  digitalWrite(SEG_SELECT_4, HIGH);
  DisplayNum(segmentdecode[convertedInUnit[3]]);
  delay(SEGMENT_SWITCH_DELAY);
  DisplayNum(0x00);//4
}

void loop() {
  if(millis() > time_now + CounterPeriod)
  {
    time_now = millis();
    Counter++;
    if(Counter > 9999)
    {
      Counter = 0;
    }
  }
 DisplayOnSegment(Counter); 
}

Here is github link for more details:

https://github.com/stechiez/electronicsDIY/tree/master/CustomSevenSegmentDisplay