Arduino with Seven Segment Display
A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment
displays are widely used in digital clocks, electronics meters, basic calculators, and other electronic devices that display numerical information. Learn more...
Seven Segment Display
Here, we will make a simple counter using Arduino, seven-segment display and the 74HC595 shift register to control the display. Our counter will count from 0-9. You can combine multiple seven-segment displays to display multiple numbers, such as in a timer project.
Schematic
Sketch
​
// define the LED digit patterns, from 0 - 9
byte seven_seg_digits[10] = {
B11111100, // = 0
B01100000, // = 1
B11011010, // = 2
B11110010, // = 3
B01100110, // = 4
B10110110, // = 5
B10111110, // = 6
B11100000, // = 7
B11111110, // = 8
B11100110 // = 9};
// connect the ST_CP of 74HC595 to pin3 on the Uno
int latchPin = 2;
// connect the SH_CP of 74HC595 to pin4 on the Uno
int clockPin = 4;
// connect the DS of 74HC595 to pin2 on the Uno
int dataPin = 3;
void setup() {
// Set latchPin, clockPin, dataPin as output
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
}
// display a number on the digital segment display
void sevenSegWrite(byte digit) {
// set the latchPin to low, before sending data
digitalWrite(latchPin, LOW);
// the original data (bit pattern)
shiftOut(dataPin, clockPin, LSBFIRST, seven_seg_digits[digit]);
// set the latchPin to high, after sending data
digitalWrite(latchPin, HIGH);
}
void loop() {
// count from 9 to 0
for (byte digit = 10; digit > 0; --digit) {
delay(1000);
sevenSegWrite(digit - 1);
}
// pause for 3 seconds
delay(3000);
}
​
Upload the above sketch to your Arduino and watch the seven-segment display make a count down from 9-0, pauses for three seconds then start over.