在这里插入代码片
DHT11有三个IO接口,一个VCC(正极)接3.3v,一个GND接GND,剩下一个DATA接树莓派的任意一个GPIO。在设备上有印刷的字体标明了引脚,可以根据指示接到树莓派上。
使用开源类库Adafruit_DHT获取温湿度
读取温度和湿度我们可以使用已经封装好的开源库:Adafruit_DHT
import Adafruit_DHT
Use read_retry method. This will retry up to 15 times to
get a sensor reading (waiting 2 seconds between each retry).
this is bcm code
humidity, temperature = Adafruit_DHT.read_retry(Adafruit_DHT.DHT11, 4)
构建数据存储部分
为了便于我们读写MySql,我们需要一个 MySqlHelper.py,内容如下:
coding=utf-8
import pymysql
from Utility.Configs import Cfg_MySql
class MySqlHelper:
conn = None
def __init__(self, db):
cfg_mysql = Cfg_MySql()
self.conn = pymysql.connect(host=cfg_mysql.get('host'), port=int(cfg_mysql.get('port')), user=cfg_mysql.get('user'), passwd=cfg_mysql.get('passwd'), db=db)
def getConnAndCur(self):
return self.conn,self.conn.cursor()
def executeSql(self,sql):
conn,cur = self.getConnAndCur()
cur.execute(sql)
conn.commit()
cur.close()
conn.close()
用完记得释放
cur.close()
conn.close()
mysql的连接信息是通过ini配置文件存储的,我们还需要一个 Configs.py 读写配置文件,内容如下:
coding=utf-8
import configparser
树莓派的ubuntu系统里面如果要使用计划任务,则必须写成绝对路径,意味着这里需要加前缀
RASPBERRY_PI_PATH = ‘/7tniy/SevenTiny.SmartHome’
Windows调试不需要加绝对路径
RASPBERRY_PI_PATH_ROOT = ‘’
get configuration
config = configparser.ConfigParser()
config.read(RASPBERRY_PI_PATH_ROOT + ‘SmartHome.ini’,encoding=‘UTF-8’)
class Cfg_MySql:
__tag = 'MySql'
def __init__(self):
pass
def get(self, name):
return config.get(self.__tag, name)
我们的配置文件 SmartHome.ini 放在项目根目录即可。内容如下:
[MySql]
connectionstring = 1
host = 192.168.0.1
port = 3306
user = prod
passwd = 123456xxx
数据库表结构:
/*
Navicat MySQL Data TransferSource Server :
Source Server Version : 50644
Source Host :
Source Database : SmartHomeTarget Server Type : MYSQL
Target Server Version : 50644
File Encoding : 65001Date: 2019-10-08 21:38:09
*/SET FOREIGN_KEY_CHECKS=0;
– Table structure for DailyMonitor
DROP TABLE IF EXISTS DailyMonitor
;
CREATE TABLE DailyMonitor
(Id
int(11) NOT NULL AUTO_INCREMENT,DateTime
datetime NOT NULL ON UPDATE CURRENT_TIMESTAMP,Year
int(11) DEFAULT NULL,Month
int(11) DEFAULT NULL,Day
int(11) DEFAULT NULL,Hour
int(11) DEFAULT NULL,Temperature
double(255,0) DEFAULT NULL,Humidity
double(255,0) DEFAULT NULL,
PRIMARY KEY (Id
)
) ENGINE=InnoDB AUTO_INCREMENT=1211 DEFAULT CHARSET=utf8;
主监控脚本 SmartHomeScreen.py 内容
创建mysql连接
通过DHT11获取温湿度
将数据异步写入MySql(每小时一次)
coding=utf-8
from Utility.MySqlHelper import MySqlHelper
import _thread
import Adafruit_DHT
import time
import datetime
import RPi.GPIO as GPIO
import sys
sys.path.append(’…’)def WriteToDb(timenow, year, month, day, hour, temp, humi):
smartHomeDb = MySqlHelper(“SmartHome”)
smartHomeDb.executeSql(“INSERT INTO DailyMonitor (DateTime,Year,Month,Day,Hour,Temperature,Humidity) VALUES (’{0}’,{1},{2},{3},{4},{5},{6})”.format(
timenow, year, month, day, hour, temp, humi))
已经写入数据库的小时标识,插入数据的同时,修改为下一个小时,用于比较是否需要写入
hasWriteToDbHour = datetime.datetime.now().hour
while(True):
# time
timenow = datetime.datetime.now()
# Use read_retry method. This will retry up to 15 times to
# get a sensor reading (waiting 2 seconds between each retry).
# this is bcm code
humidity, temperature = Adafruit_DHT.read_retry(Adafruit_DHT.DHT11, 4)
print('time:{0},humidity:{1}%,temperature:{2}*C'.format(
datetime.datetime.now(), humidity, temperature))
# 异步将数据写入mysql
if hasWriteToDbHour == timenow.hour:
_thread.start_new_thread(WriteToDb, (timenow, timenow.year,
timenow.month, timenow.day, timenow.hour, temperature, humidity))
if hasWriteToDbHour == 23:
hasWriteToDbHour = 0
else:
hasWriteToDbHour = hasWriteToDbHour + 1
time.sleep(2)
【温湿度监控】
我们通过SSH远程连接到树莓派的终端
PI
通过FTP将我们的项目上传到树莓派服务器
采用后台进程的方式运行我们的主脚本(关闭终端进程不会退出)
nohup python SmartHomeScreen.py
这样我们的信息采集脚本就一直在工作中了,每小时会采集一次温湿度,并存储到数据库表中。
【注意事项】
树莓派中默认安装的python版本是2.7,我们的代码是采用python3编写的,可能有不兼容的情况,需要重新安装python3.6以上版本
我们的GPIO类库是不能在没有GPIO支持的设备上调试的,也就是说在windows本地调试毫无意义,并且安装GPIO的包会出现各种问题,建议直接将代码复制到树莓派调试,无需在本地调试