樹莓派GPIO入門(五) ：簡易電子鐘

一、實驗要求

利用樹莓派驅動數碼管，使其能顯示時間和日期。通過按鍵，可以在時間和日期之間切換

二、實驗材料

• 按鍵1個
• 4位8段數碼管(共陰極) 1個
• 杜邦線若干
• 樹莓派4B、RPi.GPIO庫

三、原理介紹

關於如何驅動數碼管請參考：《樹莓派GPIO入門(四) ：用數碼管做個簡單的計數器》

四、實驗代碼

import RPi.GPIO as GPIO 
import time

GPIO.setmode(GPIO.BCM)

# 定義單個數碼管各段led對應的GPIO口
LED_A = 26
LED_B = 19
LED_C = 13
LED_D = 6
LED_E = 5
LED_F = 22
LED_G = 27
LED_DP = 17
LED_pins = [LED_A,LED_B,LED_C,LED_D,LED_E,LED_F,LED_G]

# 定義1到4號數碼管陰極對應的GPIO口
DIG1 = 12
DIG2 = 16
DIG3 = 20
DIG4 = 21
All_dig = [DIG1, DIG2, DIG3, DIG4]
All_pins = [LED_A,LED_B,LED_C,LED_D,LED_E,LED_F,LED_G,LED_DP,DIG1,DIG2,DIG3,DIG4]

# 定義按鈕輸入的GPIO口
btn = 24
GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_UP)  #在24號引腳處設置上拉電阻

#將數碼管LED段引腳設置爲輸出模式
GPIO.setup(All_pins, GPIO.OUT)


#0-9的各段LED狀態,1表示高電平，0表示低電平
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]


#初始化，讓所有LED段熄滅狀態
GPIO.output(All_pins, False)


def showDigit(order, num, showDotPoint):
    # 先將負極拉高，關掉顯示
    GPIO.output(All_dig, True)
    
    if (num == 0):
        GPIO.output(LED_pins, zero)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 1):
        GPIO.output(LED_pins, one)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 2):
        GPIO.output(LED_pins, two)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 3):        
        GPIO.output(LED_pins, three)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 4):
        GPIO.output(LED_pins, four)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 5):
        GPIO.output(LED_pins, five)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 6):
        GPIO.output(LED_pins, six)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 7):
        GPIO.output(LED_pins, seven)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 8):
        GPIO.output(LED_pins, eight)    
        GPIO.output(LED_DP, showDotPoint)
    elif (num == 9):
        GPIO.output(LED_pins, nine)    
        GPIO.output(LED_DP, showDotPoint)
    
    if (order == 1):
        GPIO.output(DIG1, False)
    elif (order == 2):
        GPIO.output(DIG2, False)
    elif (order == 3):
        GPIO.output(DIG3, False)
    elif (order == 4):
        GPIO.output(DIG4, False)
        
try:
    t=0.005
    while True:
        # 按鈕按下時顯示日期，否則顯示時間
        # 爲了區別左右的數字，讓第二個數碼管的小數點顯示出來
        #（本來應該是一個冒號，我們這個數碼管沒有，就用小數點代替了）
        if (GPIO.input(btn) == 0):
            time.sleep(t)
            showDigit(1, int(int(time.strftime("%m",time.localtime()))/10), False)  #月份的第一位
            time.sleep(t)
            showDigit(2, int(int(time.strftime("%m",time.localtime()))%10), True)   #月份的第二位
            time.sleep(t)
            showDigit(3, int(int(time.strftime("%d",time.localtime()))/10), False)  #日的第一位
            time.sleep(t)
            showDigit(4, int(int(time.strftime("%d",time.localtime()))%10), False)  #日的第二位
        else:
            time.sleep(t)
            showDigit(1, int(int(time.strftime("%M",time.localtime()))/10), False)  #時的第一位  
            time.sleep(t)
            showDigit(2, int(int(time.strftime("%M",time.localtime()))%10), True)   #時的第二位 
            time.sleep(t)
            showDigit(3, int(int(time.strftime("%S",time.localtime()))/10), False)  #分的第一位
            time.sleep(t)
            showDigit(4, int(int(time.strftime("%S",time.localtime()))%10), False)  #分的第二位
            
except KeyboardInterrupt:
    pass
GPIO.cleanup()  #最後清理GPIO口

五、視頻演示

由於採用的是四位數碼管，所以在顯示時間時只能顯示出當前時間的分和秒，日期只能顯示月和日。 

簡易電子鐘