与 IoT 相关的云端服务为数众多，例如：ThingSpeak、WoT.City、AWS、IBM Bluemix、MediaTek MCS、Google Firebase 等，并在透过这些云端服务可在对数据进行数据可视化、数据分析与其它的应用，而本文用Python将透过 Raspberry Pi 采集到的温湿度信息传送到 AWS IoT。

情境

材料与准备

1.准备 Raspberry Pi 3Model B 开发板

2.准备 Micro SD (已安装 Raspbian)

3.将 Micro SD 装入到 RaspberryPi 中

4.设定好网络

5.安装 GrovePi+

6.安装 Grove – Temperatureand Humidity Sensor (D4)

7.安装 GROVE - LCD RGBBACKLIGHT (I2C-2)

8.安装 IDE ( Sublime Textor Visual Studio Code )

Sensor, LCD, GrovePi+ 与 RaspberryPi 连接如下图

AWS IoT 端

Step 1. 到 AWS 网站申请账号

Step 2. 登入 AWS 网站

Step 3. 点击 Services AWS IoT

Step 4. 点击 Create a resource

Step 5. 点击 Create a thing 输入 thing Name Create

Step 6. 点击刚建立的 thing

Step 7. 点击 Connect a device

Step 8. 点击 Node.js Generate certificate and policy

Step 9. 下载 private 与 public keys

Step 10. 点击 Confirm &connecting

Step 11. 点击 Return to ThingDetail

Raspberry Pi 端

Step 1. 透过 Python 读取温湿度信息并传送到AWS IoT

#****************************************************

# Import Package

#****************************************************

import time

import datetime

import paho.mqtt.client as paho

import json

import ssl

import sys

sys.path.append('/home/pi/rpi/code/Package')

import grovepi

from grove_rgb_lcd import *

#****************************************************

# Set Pin No, AWS Config

#****************************************************

sensor = 4

blue = 0   # The Blue colored sensor.

white = 1  # The White colored sensor.

connflag = False

#****************************************************

# Set AWS Connection

#****************************************************

def on_connect(client, userdata, flags,rc):

global connflag

connflag = True

print("Connection returned result: " + str(rc) )

def on_message(client, userdata, msg):

print(msg.topic+" "+str(msg.payload))

mqttc = paho.Client()

mqttc.on_connect = on_connect

mqttc.on_message = on_message

awshost = "a3iprlpgye4dmu.iot.us-west-2.amazonaws.com"

awsport = 8883

clientId = "sensorData"

thingName = "sensorData"

caPath = "./root-CA.crt"

certPath ="./000cd28455-certificate.pem.crt"

keyPath = "./000cd28455-private.pem.key"

mqttc.tls_set(caPath, certfile=certPath, keyfile=keyPath,cert_reqs=ssl.CERT_REQUIRED, tls_version=ssl.PROTOCOL_TLSv1_2, ciphers=None)

mqttc.connect(awshost, awsport, keepalive=60)

mqttc.loop_start()

#****************************************************

# Publish AWS

#****************************************************

while True:

[temp,humidity] = grovepi.dht(sensor,blue)

print("temp = %.02f C humidity =%.02f%%"%(temp, humidity))

t= time.time();

date = datetime.datetime.fromtimestamp(t).strftime('%Y%m%d%H%M%S')

if connflag == True:

mqttc.publish("topic/sensorData",json.dumps({"time": date, "temperature": temp,"humidity": humidity}), qos=1)

else:

print("waiting for connection...")

time.sleep(1)

Step 2. 将 Python Code 与 Keys 传送到 RaspberryPi

Step 3. 执行刚传到 Raspberry Pi 中的 Python 代码，python 檔名.py

Step 4. Console 执行画面

作者：Archer Huang