Four Digit Seven Segment Display Tutorial Enhancement

1//LostGhost-2020.06.03
2
3int latch=3;  //74HC595  pin 9 STCP
4int  clock=4; //74HC595  pin 10 SHCP
5int data=2;   //74HC595  pin 8 DS
6
7unsigned  char table[]=
8{0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c
9,0x39,0x5e,0x79,0x71,0x00};//Display  digital data
10
11const int nbrDigits= 4; // the number of digits in the LED display
12                             //dig 1 2 3 4
13const int digitPins[nbrDigits] = {  5,6,7,8};
14
15int lightPin = 0; //LDR
16
17void setup() {
18  //Configuring  output pins for the 74HC595
19  pinMode(latch,OUTPUT);
20  pinMode(clock,OUTPUT);
21  pinMode(data,OUTPUT);
22
23  //Configuring output pins for commun cathod of  each 7 segment digit
24  for(int i=0; i < nbrDigits; i++)
25  {
26     pinMode(digitPins[i],  OUTPUT);
27     digitalWrite(digitPins[i],HIGH);
28  }
29}
30
31void loop()  {
32  int digitalReading  = analogRead(lightPin);
33  DisplayNumber(digitalReading);
34  delay(1);
35}
36
37//Function to display a nmuber on 4 digit 7 segments (maximum  9999)
38void DisplayNumber( int number) {
39  if(number == 0)
40    DisplayDigit(  0, nbrDigits-1) ; // display 0 in the rightmost digit
41  else
42  {
43    //  display the value corresponding to each digit
44    // leftmost digit is 0, rightmost  is one less than the number of places
45    for( int digit = nbrDigits-1; digit  >= 0; digit--)
46    {
47      if(number > 0)
48      {
49        DisplayDigit(  number % 10, digit) ;
50        number = number / 10;
51      }
52    }
53  }
54}
55
56//Function  to display on one seven segments digit
57void DisplayDigit(unsigned char num, int  digit) {
58  digitalWrite(latch,LOW);
59  shiftOut(data,clock,MSBFIRST,table[num]);
60  digitalWrite(latch,HIGH);
61  
62  digitalWrite( digitPins[digit], LOW );
63  delay(4);
64  digitalWrite( digitPins[digit], HIGH );
65}