初步设想

之前买了一个早鸟唤醒的“光闹钟”，即使用灯光唤醒。但不知是哪里出了问题，尝试了几天闹钟既没能亮也没能响，遂火速退货。于是想着何不用树莓派自制一个呢？

材料清单

  • 树莓派3B+
  • 树莓派zero
  • 压电式蜂鸣器
  • LED小灯泡
  • 按钮式开关
  • 跳线若干

说明：

之所以我用了两个树莓派，是因为树莓派zero性能较差而树莓派3B+价格较高（我买的二手的，￥220）。又考虑到二者的GPIO几乎一样（见下两图），所以便使用树莓派3B+进行研发测试，而使用树莓派zero作为最终产品。

R-Pi-3-B-Pinout.png
RPI-Zero-Pinout.png

Raspbian的使用

参考：Raspberry Pi Basics: installing Raspbian and getting it up and running (howtoforge.com)

树莓派系统对时

参考：Debian/Ubuntu 时区和自动校时设置_debian时间校准-CSDN博客

所需Python包

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import gpiozero
import time
import threading as thr
import smbus

设定时间的调节

电路连接

设定时间主要是通过两个按钮（一个设定小时，一个设定分钟）实现的。

设定时间的调节.jpg

代码实现

首先定义两个按钮

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buttonH = gpiozero.Button(22)
buttonM = gpiozero.Button(15)

在项目目录下新建两个文件分别为minute和hour用来存储我们的时间，并在里面先输入两个值作为初始值。

编写调节函数：

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def format(num):
	if num >= 10:
		return str(num)
	if num < 10:
		return "0" + str(num)

def setMin():
    with open("minute", "r") as minute_file:
        minutes = int(minute_file.read())
    print(minutes)
    while True:
        if buttonM.is_pressed:
            if minutes - 60 >= -1:
                minutes = minutes - 59
            else:
                minutes += 1
            with open("minute", "w") as minute_file:
                minute_file.write(str(minutes))
            print(minutes)
        time.sleep(0.2)


def setHour():
    with open("hour", "r") as hour_file:
        hours = int(hour_file.read())
    print(hours)
    while True:
        if buttonH.is_pressed:
            if hours - 24 >= -1:
                hours = hours - 23
            else:
                hours += 1
            with open("hour", "w") as hour_file:
                hour_file.write(str(hours))
            print(format(hours))            
        time.sleep(0.2)

上面的format()函数用于将个位数变为"0"+数字的形式，便于后续在LCD显示屏上显示。

设定时间和当前时间的显示

在这里，我们选用LCD显示屏。有关树莓派和LCD屏幕的更多信息，可以参考：树莓派通过 I2C 驱动 LCD1602 液晶屏 | 树莓派实验室 (nxez.com)

电路连接

连接LCD.jpg

所需库的写入

复制以下这段代码

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import time
import smbus
BUS = smbus.SMBus(1)
LCD_ADDR = 0x27
BLEN = 1 #turn on/off background light
 
def turn_light(key):
    global BLEN
    BLEN = key
    if key ==1 :
        BUS.write_byte(LCD_ADDR ,0x08)
    else:
        BUS.write_byte(LCD_ADDR ,0x00)
 
def write_word(addr, data):
    global BLEN
    temp = data
    if BLEN == 1:
        temp |= 0x08
    else:
        temp &= 0xF7
    BUS.write_byte(addr ,temp)
 
def send_command(comm):
    # Send bit7-4 firstly
    buf = comm & 0xF0
    buf |= 0x04               # RS = 0, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)
     
    # Send bit3-0 secondly
    buf = (comm & 0x0F) << 4
    buf |= 0x04               # RS = 0, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)
 
def send_data(data):
    # Send bit7-4 firstly
    buf = data & 0xF0
    buf |= 0x05               # RS = 1, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)
     
    # Send bit3-0 secondly
    buf = (data & 0x0F) << 4
    buf |= 0x05               # RS = 1, RW = 0, EN = 1
    write_word(LCD_ADDR ,buf)
    time.sleep(0.002)
    buf &= 0xFB               # Make EN = 0
    write_word(LCD_ADDR ,buf)
 
def init_lcd():
    try:
        send_command(0x33) # Must initialize to 8-line mode at first
        time.sleep(0.005)
        send_command(0x32) # Then initialize to 4-line mode
        time.sleep(0.005)
        send_command(0x28) # 2 Lines & 5*7 dots
        time.sleep(0.005)
        send_command(0x0C) # Enable display without cursor
        time.sleep(0.005)
        send_command(0x01) # Clear Screen
        BUS.write_byte(LCD_ADDR ,0x08)
    except:
        return False
    else:
        return True
 
def clear_lcd():
    send_command(0x01) # Clear Screen
 
def print_lcd(x, y, str):
    if x < 0:
        x = 0
    if x > 15:
        x = 15
    if y <0:
        y = 0
    if y > 1:
        y = 1
 
    # Move cursor
    addr = 0x80 + 0x40 * y + x
    send_command(addr)
     
    for chr in str:
        send_data(ord(chr))
 
if __name__ == '__main__':
    init_lcd()
    print_lcd(0, 0, 'Hello, world!')

保存为LCD1602.py于项目目录下。

显示

编写函数，实现实时显示：

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def screening():
    while True:
        t = time.localtime()
        hour = t.tm_hour
        minute = t.tm_min
        lcd.print_lcd(0, 1, "NOW:")
        lcd.print_lcd(0, 0, "ALARM AT:")
        lcd.print_lcd(9, 1, format(hour) + ":" + format(minute))
        with open("minute", "r") as minute_file:
            minutes = int(minute_file.read())
        print(minutes)
        lcd.print_lcd(12, 0, format(minutes))
        with open("hour", "r") as hour_file:
            hours = int(hour_file.read())
        print(hours)
        lcd.print_lcd(9, 0, format(hours) + ":")
        time.sleep(0.1)

注意，下面使用这个函数时需要先初始化LCD屏幕：

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lcd.init_lcd()

声闹钟实现

电路连接

连接蜂鸣器.jpg

代码实现

定义蜂鸣器：

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buzzer = gpiozero.Buzzer(26)

蜂鸣：

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def buzzing():
    buzzer.on()
    time.sleep(0.5)
    buzzer.off()
    time.sleep(0.5)