7 Segment Display Interface with Arduino Uno: Count Down Timer

 

Circuit Diagram

Program Code

byte seven_seg_digits[10][7] = { { 1, 1, 1, 1, 1, 1, 0 }, // = 0

{ 0, 1, 1, 0, 0, 0, 0 }, // = 1

{ 1, 1, 0, 1, 1, 0, 1 }, // = 2

{ 1, 1, 1, 1, 0, 0, 1 }, // = 3

{ 0, 1, 1, 0, 0, 1, 1 }, // = 4

{ 1, 0, 1, 1, 0, 1, 1 }, // = 5

{ 1, 0, 1, 1, 1, 1, 1 }, // = 6

{ 1, 1, 1, 0, 0, 0, 0 }, // = 7

{ 1, 1, 1, 1, 1, 1, 1 }, // = 8

{ 1, 1, 1, 0, 0, 1, 1 } // = 9

};

// Set the seven-segment LED pins as output

void setup() {

pinMode(2, OUTPUT);

pinMode(3, OUTPUT);

pinMode(4, OUTPUT);

pinMode(5, OUTPUT);

pinMode(6, OUTPUT);

pinMode(7, OUTPUT);

pinMode(8, OUTPUT);

pinMode(9, OUTPUT);

writeDot(0); // Start with the decimal point off

}

void writeDot(byte dot) {

digitalWrite(9, dot);

}

void sevenSegWrite(byte digit) {

byte pin = 2;

for (byte segCount = 0; segCount < 7; ++segCount) {

digitalWrite(pin, seven_seg_digits[digit][segCount]);

++pin;

}

}

void loop() {

for (byte count = 10; count > 0; --count) { // Start the countdown

delay(1000); // 1 second between each digit

sevenSegWrite(count - 1); // Counting down by 1

}

delay(4000);

}