與 IoT 相關的云端服務為數眾多，例如：ThingSpeak、WoT．City、AWS、IBM Bluemix、MediaTek MCS、Google Firebase 等，并在透過這些云端服務可在對數據進行數據可視化、數據分析與其它的應用，而本文用Python將透過 Raspberry Pi 采集到的溫濕度信息傳送到 AWS IoT。

情境

材料與準備

1．準備 Raspberry Pi 3Model B 開發板

2．準備 Micro SD （已安裝 Raspbian）

3．將 Micro SD 裝入到 RaspberryPi 中

4．設定好網絡

5．安裝 GrovePi＋

6．安裝 Grove – Temperatureand Humidity Sensor （D4）

7．安裝 GROVE － LCD RGBBACKLIGHT （I2C－2）

8．安裝 IDE （ Sublime Textor Visual Studio Code ）

Sensor， LCD， GrovePi＋ 與 RaspberryPi 連接如下圖

AWS IoT 端

Step 1． 到 AWS 網站申請賬號

Step 2． 登入 AWS 網站

Step 3． 點擊 Services AWS IoT

Step 4． 點擊 Create a resource

Step 5． 點擊 Create a thing 輸入 thing Name Create

Step 6． 點擊剛建立的 thing

Step 7． 點擊 Connect a device

Step 8． 點擊 Node．js Generate certificate and policy

Step 9． 下載 private 與 public keys

Step 10． 點擊 Confirm ＆connecting

Step 11． 點擊 Return to ThingDetail

Raspberry Pi 端

Step 1． 透過 Python 讀取溫濕度信息并傳送到AWS IoT

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＃ Import Package

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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 ＊

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＃ Set Pin No， AWS Config

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sensor ＝ 4

blue ＝ 0 ＃ The Blue colored sensor．

white ＝ 1 ＃ The White colored sensor．

connflag ＝ False

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＃ Set AWS Connection

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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（）

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＃ Publish AWS

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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． 將 Python Code 與 Keys 傳送到 RaspberryPi

Step 3． 執行剛傳到 Raspberry Pi 中的 Python 代碼，python 檔名．py

Step 4． Console 執行畫面

作者：Archer Huang