Build a DIY Smart Alarm Clock on Raspberry Pi with Python and Cron

Introduction

The author, while working on a smart factory project, decided to build a simple alarm clock using a Raspberry Pi 3B+, Python, and a few peripheral devices. The clock announces the weather and plays a random music file each morning.

Hardware List

RFID reader and an SD card for the OS

3.5 mm speaker

SSH client (SecureCRT, Xshell)

Broadband router (already available at home)

Raspberry Pi 3B+ with charger and CPU cooling fan

Python Dependencies

Install the required Python packages on the Pi:

pip3 install pygame

pip3 install baidu-aip

Core Code Overview

The script performs three main tasks: fetch weather data, synthesize speech, and play audio.

Fetching Weather

import urllib.request, json

def get_weather():
    url = 'http://www.weather.com.cn/data/cityinfo/101120201.html'
    obj = urllib.request.urlopen(url)
    data_b = obj.read()
    data_s = data_b.decode('utf-8')
    data_dict = json.loads(data_s)
    rt = data_dict['weatherinfo']
    weather = ('亲爱的：该起床了，别睡了，快变小猪了，哈哈哈哈哈，我想你了，' +
               '你想我吗？青岛的温度是 {} 到 {}，天气 {}').format(
                   rt['temp1'], rt['temp2'], rt['weather'])
    if '雨' in weather:
        weather += '今天别忘记带雨伞哦！'
    du_say(weather)

Text‑to‑Speech with Baidu AI

from aip import AipSpeech

def du_say(weather):
    app_id = '****'
    api_key = '****'
    secret_key = '****'
    client = AipSpeech(app_id, api_key, secret_key)
    result = client.synthesis(weather, 'zh', 1, {'vol':5,'per':3,'spd':4})
    if not isinstance(result, dict):
        with open('weather.mp3', 'wb') as f:
            f.write(result)
        py_game_player('weather.mp3')

Audio Playback

import pygame, random

def py_game_player(file):
    pygame.mixer.init()
    print('播报天气')
    pygame.mixer.music.load(file)
    pygame.mixer.music.play(loops=1, start=0.0)
    print('播放音乐')
    while True:
        if pygame.mixer.music.get_busy() == 0:
            mp3 = "/home/pi/alarmClock/" + str(random.randint(1,6)) + ".mp3"
            pygame.mixer.music.load(mp3)
            pygame.mixer.music.play(loops=1, start=0.0)
            break
    while True:
        if pygame.mixer.music.get_busy() == 0:
            print('播报完毕，起床啦')
            break

Main Execution

if __name__ == '__main__':
    get_weather()

Cron Scheduling

To run the alarm automatically each morning, add a cron entry:

# Edit crontab for the pi user
crontab -e
# Example entry for 7:00 AM
00 07 * * * python3 /home/pi/alarmClock/play.py

After saving, verify the system time zone (the default may not be China/Shanghai) and adjust if necessary:

date                     # check current time
sudo dpkg-reconfigure tzdata   # select Asia/Shanghai

Conclusion

The resulting device is a basic, non‑intelligent alarm clock that announces the weather and plays a random music track. Although simple, the project demonstrates how to combine Raspberry Pi hardware, Python scripting, Baidu AI speech synthesis, and Linux scheduling to create a customizable DIY IoT gadget.