Three digit - 7 segment Display

7-Segment

7 Segment Display has seven segments in it and each segment has one LED inside it to display the numbers by lighting up the corresponding segments. Like if you want the 7-segment to display the number "5" then you need to glow segment a,f,g,c, and d by making their corresponding pins high. There are two types of 7-segment displays: Common Cathode and Common Anode, here we are using Common Cathode seven segment display. 

Now we know how to display our desired numeric character on a single 7-segment display. But, it is pretty evident that we would need more than one 7-segment display to convey any information that is more than one digit. So, in this tutorial we will be using a 3-digit 7-Segment Display Module as shown below.

Below is the Schematics for 3 digit-7 segment display.

Following python code can be used to turn the LED on or off.

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import RPi.GPIO as GPIO
import time, datetime

now = datetime.datetime.now()

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
 
 #GPIO ports for the 7seg pins
segment8 =  (26,19,13,6,5,11,9,10)

 
for segment in segment8:
    GPIO.setup(segment, GPIO.OUT)
    GPIO.output(segment, 0)
 
    #Digit 1
    GPIO.setup(7, GPIO.OUT)
    GPIO.output(7, 0) #Off initially
    #Digit 2
    GPIO.setup(8, GPIO.OUT)
    GPIO.output(8, 0) #Off initially
    #Digit 3
    GPIO.setup(25, GPIO.OUT)
    GPIO.output(25, 0) #Off initially
    #Digit 4
    GPIO.setup(24, GPIO.OUT)
    GPIO.output(24, 0) #Off initially

null = [0,0,0,0,0,0,0]
zero = [1,1,1,1,1,1,0]
one = [0,1,1,0,0,0,0]
two = [1,1,0,1,1,0,1]
three = [1,1,1,1,0,0,1]
four = [0,1,1,0,0,1,1]
five = [1,0,1,1,0,1,1]
six = [1,0,1,1,1,1,1]
seven = [1,1,1,0,0,0,0]
eight = [1,1,1,1,1,1,1]
nine = [1,1,1,1,0,1,1]

def print_segment(charector):
    if charector == 1:
        for i in range(7):
            GPIO.output(segment8[i], one[i])

    if charector == 2:
        for i in range(7):
            GPIO.output(segment8[i], two[i])

    if charector == 3:
        for i in range(7):
            GPIO.output(segment8[i], three[i])

    if charector == 4:
        for i in range(7):
            GPIO.output(segment8[i], four[i])

    if charector == 5:
        for i in range(7):
            GPIO.output(segment8[i], five[i])

    if charector == 6:
        for i in range(7):
            GPIO.output(segment8[i], six[i])

    if charector == 7:
        for i in range(7):
            GPIO.output(segment8[i], seven[i])

    if charector == 8:
        for i in range(7):
            GPIO.output(segment8[i], eight[i])

    if charector == 9:
        for i in range(7):
            GPIO.output(segment8[i], nine[i])

    if charector == 0:
        for i in range(7):
            GPIO.output(segment8[i], zero[i])        
            
    return;

while 1:

    now = datetime.datetime.now()
    hour = now.hour
    minute = now.minute
    h1 = hour/10
    h2 = hour % 10
    m1 = minute /10
    m2 = minute % 10
    print (h1,h2,m1,m2)

  
    delay_time = 0.001 #delay to create virtual effect
    
    
    GPIO.output(7, 1) #Turn on Digit One
    print_segment (h1) #Print h1 on segment
    time.sleep(delay_time)
    GPIO.output(7, 0) #Turn off Digit One

    GPIO.output(8, 1) #Turn on Digit One
    print_segment (h2) #Print h1 on segment
    GPIO.output(10, 1) #Display point On
    time.sleep(delay_time)
    GPIO.output(10, 0) #Display point Off
    GPIO.output(8, 0) #Turn off Digit One

    GPIO.output(25, 1) #Turn on Digit One
    print_segment (m1) #Print h1 on segment
    time.sleep(delay_time)
    GPIO.output(25, 0) #Turn off Digit One

    GPIO.output(24, 1) #Turn on Digit One
    print_segment (m2) #Print h1 on segment
    time.sleep(delay_time)
    GPIO.output(24, 0) #Turn off Digit One
 
    #time.sleep(1)