【物联网实训项目】------（四）家庭智慧安防系统之智能温控

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原创最新推荐文章于 2026-06-05 17:32:49 发布 2.5k 阅读 AI 写同款· GEO 优化 ›

Python之adafruit-dht包语法、参数和实际应用案例 adafruit-dht 是一个用于与 DHT 系列温湿度传感器（如 DHT11、DHT22、AM2302）进行交互的 Python 库，特别适用于树莓派等单板计算机。它简化了传感器数据的读取过程，提供了简洁的 API 接口。阅读详情

1.所需材料:

树莓派、面包板、温湿度传感器DHT11、直流电机、风扇、L298N电机驱动模块。

2.树莓派从DHT11温湿度传感器读取数据

（1）DHT11 介绍

DHT11是一款有已校准数字信号输出的温湿度传感器。其精度湿度+-5%RH，温度+-2℃，量程湿度20-90%RH，温度0~50℃。

（2）硬件连接图

（3）具体流程

DHT11的读取需要遵循特定的信号协议完成，为了方便使用Adafruit DHT库。

a.软件安装

sudo apt-get install build-essential python-dev

b.从GitHub获取Adafruit库

sudo git clone https://github.com/adafruit/Adafruit_Python_DHT.git

cd Adafruit_Python_DHT

c.给python2和python3安装该库

sudo python setup.py install

sudo python3 setup.py install

d.书写dht.py程序引入Adafruit库来读取DHT11的数据

import Adafruit_DHT

  

# Set sensor type : Options are DHT11,DHT22 or AM2302

sensor=Adafruit_DHT.DHT11

  

# Set GPIO sensor is connected to

gpio=17

  

# Use read_retry method. This will retry up to 15 times to

# get a sensor reading (waiting 2 seconds between each retry).

humidity, temperature = Adafruit_DHT.read_retry(sensor, gpio)

  

# Reading the DHT11 is very sensitive to timings and occasionally

# the Pi might fail to get a valid reading. So check if readings are valid.

if humidity is not None and temperature is not None:

  print('Temp={0:0.1f}*C  Humidity={1:0.1f}%'.format(temperature, humidity))

else:

  print('Failed to get reading. Try again!')

e.运行结果图

3.树莓派从DHT11温湿度传感器读取数据写入到数据库中

（1）在树莓派上安装MySQL数据库

a.安装MySQL

使用管理员权限运行获取最新的MySQL及Python编程接口。

$ sudo apt-get install mysql-server python-mysqldb

安装过程中需要输入root管理员的密码，该密码用于之后访问数据库。

b.登录MySQL

mysql -u root -p

Enter password:

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 53

Server version: 5.5.60-0+deb8u1 (Raspbian)



Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.



Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.



Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

c.查看当前的数据库

mysql> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

+--------------------+

3 rows in set (0.00 sec)

d.创建一个新的数据库

mysql> CREATE DATABASE jiankong;

Query OK, 1 row affected (0.00 sec)

e.在jiankong数据库下创建dht2的表

mysql> use jiankong;

Database changed
mysql> create table dht2(id int auto_increment primary key not null, time char(255),temperature int,humidity int);

Query OK, 0 rows affected (0.03 sec)

f.查看表是否创建成功。

mysql> describe dht2;

+-------------+-----------+------+-----+---------+----------------+

| Field       | Type      | Null | Key | Default | Extra          |

+-------------+-----------+------+-----+---------+----------------+

| id          | int(11)   | NO   | PRI | NULL    | auto_increment |

| time        | char(255) | YES  |     | NULL    |                |

| temperature  | int(11)   | YES  |     | NULL    |                |

| humidity    | int(11)   | YES  |     | NULL    |                |

+-------------+-----------+------+-----+---------+----------------+

4 rows in set (0.00 sec)

（2）在树莓派上通过python来对mysql数据库进行存储操作

书写测试文件mysql_test.py来测试是否成功

import MySQLdb

sql='show databases';

conn=MySQLdb.connect(host='localhost',user='root',passwd='root',db='jiankong',port=3306)

cur=conn.cursor(

cur.execute(sql)

print cur.fetchone()

测试成功结果图

（3）将树莓派读取到的温湿度信息写入到我们mysql数据库，对dht.py文件进行修改

#coding: utf8

import Adafruit_DHT

import MySQLdb  

import datetime

#引入gpio的模块

import RPi.GPIO as GPIO

import time

# Set sensor type : Options are DHT11,DHT22 or AM2302

sensor=Adafruit_DHT.DHT11

  

# Set GPIO sensor is connected to

gpio=4

dt=datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")  



# Use read_retry method. This will retry up to 15 times to

# get a sensor reading (waiting 2 seconds between each retry).

humidity, temperature = Adafruit_DHT.read_retry(sensor, gpio)

  

# Reading the DHT11 is very sensitive to timings and occasionally

# the Pi might fail to get a valid reading. So check if readings are valid.

if humidity is not None and temperature is not None:

  print('Temp={0:0.1f}*C  Humidity={1:0.1f}%'.format(temperature, humidity))

  print "temperature:",temperature

  print "humidity:",humidity  

  conn=MySQLdb.connect(

    host='localhost',

    port=3306,

    user='root',

    passwd='root',

    db='jiankong',

  )

  sql="insert into dht2(time,temperature,humidity) values('%s','%d','%d')"%(dt,temperature,humidity)

  cur=conn.cursor()

  cur.execute(sql)

  cur.close()

  conn.commit()

  conn.close()

else:

  print('Failed to get reading. Try again!')

查看一下数据表dht2中的数据

4.树莓派结合L298N模块驱动直流电机

（1）L298N模块的介绍

接口说明：INT1、INT2、INT3、INT4分别接了树莓派的GPIO13、GPIO15、GPIO16、GPIO18。+5V接树莓派5V，GND接地。

（2）Python代码：

#!/usr/bin/python

#coding: utf8

#引入gpio的模块

import RPi.GPIO as GPIO

import time

#设置GPIO模式

GPIO.setmode(GPIO.BOARD)



#设置in1到in4接口

IN1 = 13

IN2 = 15

IN3 = 16

IN4 = 18



#初始化接口

def init():

    GPIO.setup(IN1,GPIO.OUT)

    GPIO.setup(IN2,GPIO.OUT)

    GPIO.setup(IN3,GPIO.OUT)

    GPIO.setup(IN4,GPIO.OUT)



#前进的代码

def qianjin(sleep_time):

    GPIO.output(IN1,GPIO.HIGH)

    GPIO.output(IN2,GPIO.LOW)

    GPIO.output(IN3,GPIO.HIGH)

    GPIO.output(IN4,GPIO.LOW)

    time.sleep(sleep_time)

    GPIO.cleanup()



#后退

def cabk(sleep_time):

    GPIO.output(IN1,GPIO.LOW)

    GPIO.output(IN2,GPIO.HIGH)

    GPIO.output(IN3,GPIO.LOW)

    GPIO.output(IN4,GPIO.HIGH)

    time.sleep(sleep_time)

    GPIO.cleanup()



#左转

def left(sleep_time):

    GPIO.output(IN1,False)

    GPIO.output(IN2,False)

    GPIO.output(IN3,GPIO.HIGH)

    GPIO.output(IN4,GPIO.LOW)

    time.sleep(sleep_time)

    GPIO.cleanup()



#右转

def right(sleep_time):

    GPIO.output(IN1,GPIO.HIGH)

    GPIO.output(IN2,GPIO.LOW)

    GPIO.output(IN3,False)

    GPIO.output(IN4,False)

    time.sleep(sleep_time)

    GPIO.cleanup()

init()#调用初始化方法初始化接口

cabk(10)#调用后退方法，并且10秒后停止

运行该程序，直流电机可运行10s。

5.树莓派智能调温综合

对dhp.py程序进行修改，使其测温度、湿度的时候，如果温度超过25℃，会自启动风扇降温。

#coding: utf8

import Adafruit_DHT

import MySQLdb  

import datetime

#引入gpio的模块

import RPi.GPIO as GPIO

import time

# Set sensor type : Options are DHT11,DHT22 or AM2302

sensor=Adafruit_DHT.DHT11

  

# Set GPIO sensor is connected to

gpio=4

dt=datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")  

#设置GPIO模式

GPIO.setmode(GPIO.BOARD)



#设置in1到in4接口

IN1 = 13

IN2 = 15

IN3 = 16

IN4 = 18



#初始化接口

def init():

    GPIO.setup(IN1,GPIO.OUT)

    GPIO.setup(IN2,GPIO.OUT)

    GPIO.setup(IN3,GPIO.OUT)

    GPIO.setup(IN4,GPIO.OUT)

 #后退

def cabk(sleep_time):

    GPIO.output(IN1,GPIO.LOW)

    GPIO.output(IN2,GPIO.HIGH)

    GPIO.output(IN3,GPIO.LOW)

    GPIO.output(IN4,GPIO.HIGH)

    time.sleep(sleep_time)

    GPIO.cleanup()

# Use read_retry method. This will retry up to 15 times to

# get a sensor reading (waiting 2 seconds between each retry).

humidity, temperature = Adafruit_DHT.read_retry(sensor, gpio)

  

# Reading the DHT11 is very sensitive to timings and occasionally

# the Pi might fail to get a valid reading. So check if readings are valid.

if humidity is not None and temperature is not None:

  print('Temp={0:0.1f}*C  Humidity={1:0.1f}%'.format(temperature, humidity))

  print "temperature:",temperature

  print "humidity:",humidity  

  conn=MySQLdb.connect(

    host='localhost',

    port=3306,

    user='root',

    passwd='root',

    db='jiankong',

  )

  sql="insert into dht2(time,temperature,humidity) values('%s','%d','%d')"%(dt,temperature,humidity)

  cur=conn.cursor()

  cur.execute(sql)

  cur.close()

  conn.commit()

  conn.close()

  if temperature > 25:

    init()

    cabk(30)

else:

  print('Failed to get reading. Try again!')

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