As you could see from last week’s full Arduino sketch listing, the source code for the 2-digit 7-segment display project using buttons is strikingly similar to the one without the buttons; praise for ‘copy and paste‘! (It is worth noting, though, that ‘copy and paste‘ can be responsible for a higher percentage of bugs than I’d care to admit).

There are just a couple of snippets that I would like to comment on:

The first part of the loop() function checks whether either button has been pressed and increments the value of each digit.

  // check button1
  int val1 = digitalRead(BTN1);
  if (val1 == HIGH) {
    digit1++;
    digit1 %= 10;
    delay(10);
  }

  // check button2
  int val2 = digitalRead(BTN2);
  if (val2 == HIGH) {
    digit2++;
    digit2 %= 10;
    delay(10);
  }

The line

    digit1 %= 10;

which is shorthand for

    digit1 = digit1 % 10;

accomplishes the same as the line

    if (count == 10) count = 0;

that was used on the sketch for the single-digit 7-segment project a couple of months ago. It updates digit1 with the remainder of the division of itself by 10, which will be zero when digit1 is 10. The latter code looks a bit more obvious for beginner programmers.

The last part of the loop() function refreshes the display, and is very similar to the sketch for the 2-digit 7-segment display counter.

  // display number
  unsigned long startTime = millis();
  for (unsigned long elapsed=0; elapsed < 600; elapsed = millis() - startTime) {
    lightDigit1(numbers[digit1]);
    delay(5);
    lightDigit2(numbers[digit2]);
    delay(5);
  }

You might also enjoy:

1. Arduino 2-Digit 7-Segment Display Counter: Sketch | Part 3
2. Arduino 2-Digit 7-Segment Display with Buttons | Part 4
3. Arduino 2-Digit 7-Segment Display Counter | Part 1
4. Arduino 2-Digit 7-Segment Display Counter: Circuit | Part 2

This week we modify the original circuit and sketch to include two buttons, one to control each digit of the display.

Here’s what the setup looks like:

And here’s the complete sketch:

// www.TheElectronicsHobbyist.com/blog
// Natalia Fargasch Norman
// Dual seven-segment LED Display with buttons
// Common Anode digit 1 pin 10
// Common Anode digit 2 pin 5

//       CA1 G  F  A  B
//        |  |  |  |  |      -> pins and segments they control
//   ---------    ---------
//   |   A   |    |   A   |
//  F|       |B  F|       |B
//   |---G---|    |---G---|
//  E|       |C  E|       |C
//   |   D   |    |   D   |
//   ---------    ---------
//        |  |  |  |  |      -> pins and segments they control
//        D  DP E  C CA2         

// Segments that make each number when lit:
// 0 => -FEDCBA
// 1 => ----BC-
// 2 => G-ED-BA
// 3 => G--DCBA
// 4 => GF--CB-
// 5 => GF-DC-A
// 6 => GFEDC-A
// 7 => ----CBA
// 8 => GFEDCBA
// 9 => GF-DCBA

// Arduino digital pins used to light up
// corresponding segments on the LED display
#define A 3
#define B 2
#define C 6
#define D 8
#define E 7
#define F 4
#define G 5

// Pushbuttons connected to pins 9 and 10
#define BTN1 9
#define BTN2 10

// Pins driving common anodes
#define CA1 13
#define CA2 12

// Pins for A B C D E F G, in sequence
const int segs[7] = { A, B, C, D, E, F, G };

// Segments that make each number
const byte numbers[10] = { 0b1000000, 0b1111001, 0b0100100, 0b0110000, 0b0011001, 0b0010010,
0b0000010, 0b1111000, 0b0000000, 0b0010000 };

int digit1 = 0;
int digit2 = 0;

void setup() {
  pinMode(A, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(C, OUTPUT);
  pinMode(D, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(F, OUTPUT);
  pinMode(G, OUTPUT);
  pinMode(BTN1, INPUT);
  pinMode(BTN2, INPUT);
  pinMode(CA1, OUTPUT);
  pinMode(CA2, OUTPUT);
}

void loop() {

  // check button1
  int val1 = digitalRead(BTN1);
  if (val1 == HIGH) {
    digit1++;
    digit1 %= 10;
    delay(10);
  }

  // check button2
  int val2 = digitalRead(BTN2);
  if (val2 == HIGH) {
    digit2++;
    digit2 %= 10;
    delay(10);
  }

  // display number
  unsigned long startTime = millis();
  for (unsigned long elapsed=0; elapsed < 600; elapsed = millis() - startTime) {
    lightDigit1(numbers[digit1]);
    delay(5);
    lightDigit2(numbers[digit2]);
    delay(5);
  }
}

void lightDigit1(byte number) {
  digitalWrite(CA1, LOW);
  digitalWrite(CA2, HIGH);
  lightSegments(number);
}

void lightDigit2(byte number) {
  digitalWrite(CA1, HIGH);
  digitalWrite(CA2, LOW);
  lightSegments(number);
}

void lightSegments(byte number) {
  for (int i = 0; i < 7; i++) {
    int bit = bitRead(number, i);
    digitalWrite(segs[i], bit);
  }
}

Here’s a video of the Arduino 2-digit 7-segment display counter with buttons in action.

You might also enjoy:

1. Controlling a Seven-Segment Display Using Arduino Part 3
2. Arduino 2-Digit 7-Segment Display Counter | Part 1
3. Controlling a Seven-Segment Display Using Arduino Part 4
4. Arduino 2-Digit 7-Segment Display with Buttons: Sketch | Part 5

The second sketch cycles through the numbers from 0 to 9, but only increments the display counter each time a button is pressed. Note that this code includes simple debouncing by introducing a short delay when the Arduino detects that the button has been pressed.

Sketch #2:

// www.TheElectronicsHobbyist.com/blog
// Natalia Fargasch Norman
// Seven-segment LED Display
// Common Anode pins 3 and 8

//   G F + A B
//   | | | | |   -> pins and segments they control
//   ---------
//  F|   A   |B
//   |---G---|   -> segments
//  E|   D   |C
//   ---------
//   | | | | |   -> pins and segments they control
//   E D + C DP

// Segments that make each number when lit:
// 0 => ABCDEF
// 1 => BC
// 2 => ABDEG
// 3 => ABCDG
// 4 => BCFG
// 5 => ACDFG
// 6 => ACDEFG
// 7 => ABC
// 8 => ABCDEFG
// 9 => ABCDFG

// Arduino digital pins used to light up
// corresponding segments on the LED display
#define A 2
#define B 3
#define C 4
#define D 5
#define E 6
#define F 7
#define G 8

// Pushbutton connected to pin 9
#define BUTTON 9

// Common anode;
// on when pin is low
// and off when pin is high
#define ON LOW
#define OFF HIGH

int count = 0; // current display count
int val = 0;   // digital input from button

void setup() {
  pinMode(A, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(C, OUTPUT);
  pinMode(D, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(F, OUTPUT);
  pinMode(G, OUTPUT);
  pinMode(BUTTON, INPUT);
  zero();
}

void loop() {
  val = digitalRead(BUTTON);
  if (val == HIGH) {
    count++;
    delay(200);
    switch (count) {
      case 0:
        zero();
        break;
      case 1:
        one();
        break;
      case 2:
        two();
        break;
      case 3:
        three();
        break;
      case 4:
        four();
        break;
      case 5:
        five();
        break;
      case 6:
        six();
        break;
      case 7:
        seven();
        break;
      case 8:
        eight();
        break;
      case 9: {
        nine();
        count = -1;
        break;
      }
    }
  }
}

// 0 => ABCDEF
void zero() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, ON);
  digitalWrite(F, ON);
  digitalWrite(G, OFF);
}

// 1 => BC
void one() {
  digitalWrite(A, OFF);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, OFF);
  digitalWrite(E, OFF);
  digitalWrite(F, OFF);
  digitalWrite(G, OFF);
}

// 2 => ABDEG
void two() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, OFF);
  digitalWrite(D, ON);
  digitalWrite(E, ON);
  digitalWrite(F, OFF);
  digitalWrite(G, ON);
}

// 3 => ABCDG
void three() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, OFF);
  digitalWrite(F, OFF);
  digitalWrite(G, ON);
}

// 4 => BCFG
void four() {
  digitalWrite(A, OFF);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, OFF);
  digitalWrite(E, OFF);
  digitalWrite(F, ON);
  digitalWrite(G, ON);
}

// 5 => ACDFG
void five() {
  digitalWrite(A, ON);
  digitalWrite(B, OFF);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, OFF);
  digitalWrite(F, ON);
  digitalWrite(G, ON);
}

// 6 => ACDEFG
void six() {
  digitalWrite(A, ON);
  digitalWrite(B, OFF);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, ON);
  digitalWrite(F, ON);
  digitalWrite(G, ON);
}

// 7 => ABC
void seven() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, OFF);
  digitalWrite(E, OFF);
  digitalWrite(F, OFF);
  digitalWrite(G, OFF);
}

// 8 => ABCDEFG
void eight() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, ON);
  digitalWrite(F, ON);
  digitalWrite(G, ON);
}

// 9 => ABCDFG
void nine() {
  digitalWrite(A, ON);
  digitalWrite(B, ON);
  digitalWrite(C, ON);
  digitalWrite(D, ON);
  digitalWrite(E, OFF);
  digitalWrite(F, ON);
  digitalWrite(G, ON);
}

You might also enjoy:

1. Controlling a Seven-Segment Display Using Arduino Part 4
2. Controlling a Seven-Segment Display Using Arduino Part 2
3. Arduino 2-Digit 7-Segment Display with Buttons | Part 4
4. Arduino 2-Digit 7-Segment Display Counter | Part 1