将Adafruit WICED Feather连接到AWS IoT

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点点&木木发布时间：2019-3-20 22:50

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本帖最后由点点&木木于 2019-4-12 12:01 编辑

这是Adafruit提供的将AdafruitFeather WICED连接到适用于Mac OS X / Linux的AWS IoT的说明的更新。

硬件组件

Adafruit WICED WiFi Feather - STM32F205 with Cypress WICED WiFi × 1

目的

我将向您展示如何将Adafruit WICEDFeather连接到AWS IoT。WICED Feather基于赛普拉斯WICED（嵌入式设备的无线互联网连接）平台和ARM Cortex M3处理器。

连接Raspberry Pi可能会更容易，而新的Zero W甚至更便宜。但是Raspberry Pi是一台成熟的计算机，而不是IoT（imho）意义上的东西。

我很快发现要找到连接到AWS IoT的东西并不容易。

一个原因是AWS IoT的安全层：

“与其他MQTT解决方案相比，AWS IoT脱颖而出的一个关键方面是安全层。除了使用证书验证远程MQTT服务器（类似于HTTPS的工作方式）之外，还通过以下方式验证各个传感器节点：第二个设备端证书。这意味着，设备将数据推送到MQTT代理或从中订阅数据的设备非常高，只能是您认为的设备。“

另一个原因是亚马逊提供的AWS物联网套件在德国不易获得，价格昂贵（特别是如果包含运费）并且不是最新的。我发现Adafruit WICEDFeather以及将其连接到AWS IoT 的教程。但是我很快就知道教程已经过时了，而且给定的Git存储库不再存在了。

因此，我决定使用此处给出的说明更新教程。我希望你玩得开心，它会帮助你完成你的项目。以下说明是假定您使用的是Mac OS X或Linux。

设置Adafruit WICED Feather

按照此处提供的说明操作。请注意，您的计算机上需要Python 2.7。

登录您的AWS账户并选择AWS IoT，单击“连接”，然后单击“配置设备”/“入门”：

AWS IoT：连接设备

然后选择一个平台和一个SDK。我选择了Linux / OSX和Node.js - 对于这个项目，你选择哪个SDK并不重要，直到你可以注册一个东西。输入名称并继续。我选择了“二”。下载连接套件。该套件包含：

· 私钥（要在草图文件中复制）

· 公钥（要在草图文件夹中移动）

· 证书（用pycert.py转换）

· 一个启动脚本（这里你不需要这个）

完成对话，直到您回到AWS IoT仪表板上。

ArduinoIDE

根据该图打开“Adafruit WICED Examples”/“MQTT”文件夹中名为“aws”的示例。

Arduino IDE

将草图保存到草图文件夹中。将文件从AWS IoT连接工具包复制到此文件夹。在草图副本中插入WiFi网络的SSID凭据：

#define WLAN_SSID "yourSSID" #define WLAN_PASS "yourPass"

使用订阅框旁边的“测试”窗格中的AWS IoT UI中找到的主机替换下面的主机。

#define AWS_IOT_MQTT_HOST "A1B0KY2Z6UVZ7R.iot.us-west-2.amazonaws.com"

打开下拉菜单，然后根据图中点击“Viewendpoint”：

AWS IoT：获取MQTT端点

替换客户端ID和事物名称。

#define AWS_IOT_MQTT_CLIENT_ID "feather-two" #define AWS_IOT_MY_THING_NAME "feather-two"

现在，您必须使用Adafruit提供的Python工具转换证书，这是使用WICED Feather设置安装的代码的一部分。

python ~/Library/Arduino15/packages/adafruit/hardware/wiced/0.6.2/tools/pycert/pycert.py convert -c local_cert -l LOCAL_CERT_LEN feather-two.cert.pem

请注意，我的证书名为feather-two.cert.pem。如果您为设备使用了其他名称，请更改名称。

Loaded certificate feather-two.cert.pem Wrote certificates.h

现在打开文本编辑器并加载私钥（feather-two.private.key）。在每行前后放置引号，并在每行后添加'\ n'换行符！你最终会得到这样的东西：

const charaws_private_key[] =

"-----BEGINRSA PRIVATE KEY-----\n"

"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n"

"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n"

"-----ENDRSA PRIVATE KEY-----";

用您的私钥替换行。

"-----BEGINRSA PRIVATE KEY-----\n"

"Your Keycontents line 1 with newline and quoted\n"

"Quoteeach of your key's lines like this example\n"

"-----ENDRSA PRIVATE KEY-----";

现在将草图上传到您的WICED Feather，然后单击Arduino IDE右上角的按钮打开串行监视器。在串行监视器窗口的右下角选择115200波特。

注意：我的串行控制台有些问题。我通过再次单击115200波特率条目的菜单解决了这个问题。

主题

切换到AWS IoT控制台。在物联网控制台中，单击“测试”，然后单击“订阅主题”。

AWS IoT：订阅主题

现在输入：

$aws/things/feather-two/shadow/update/accepted

作为主题的名称。这是草图中的名称：

#define AWS_IOT_MQTT_TOPIC "$aws/things/" AWS_IOT_MY_THING_NAME "/shadow/update"

添加“/ accepted”。

AWS IoT：主题订阅

生成数据

返回到Arduino IDE并通过在串行监视器的输入字段中输入0或1并按返回来生成要发布的数据。再次切换到AWS IoT控制台。您现在应该看到表单的条目：

AWS IoT：第一个MQTT消息

条目由草图中的以下代码生成。

//Serial.print("Publishing to " AWS_IOT_MQTT_TOPIC " ... "); if ( c == '0' )
{
mqtt.publish(AWS_IOT_MQTT_TOPIC, SHADOW_PUBLISH_STATE_OFF, MQTT_QOS_AT_LEAST_ONCE); // Will halted if an error occurs

}else if ( c == '1' )
{
mqtt.publish(AWS_IOT_MQTT_TOPIC, SHADOW_PUBLISH_STATE_ON, MQTT_QOS_AT_LEAST_ONCE); // Will halted if an error occurs

}

原理图

代码

/*********************************************************************

Thisis an example for our Feather WIFI modules

Pickone up today in the adafruit shop!

Adafruit invests time and resources providingthis open source code,

please support Adafruit and open-sourcehardware by purchasing

products from Adafruit!

MITlicense, check LICENSE for more information

Alltext above, and the splash screen below must be included in

anyredistribution

*********************************************************************/

#include <adafruit_feather.h>

#include <adafruit_mqtt.h>

/* This sketch connects to a AWS IOT withmutual verification.

*User enter '0' or '1' to update AWS shadow device as well as

*the LED on WICED module

* Torun this demo:

* 1.Create an account and log in http://aws.amazon.com/iot

* 2.Create a THING and named it 'led'

* 3.Select "led" thing and choose "Connect a Device", thenselect "Embeeded C" and click "Genereate Certificate andPolicy"

* 4.Download the generated certificate and private key to this sketch folder. Thenclick "Confirm & Start connecting"

* 5.Then You could see these AWS_IOT_MQTT_HOST, AWS_IOT_MQTT_PORT,AWS_IOT_MQTT_CLIENT_ID, AWS_IOT_MY_THING_NAME, copy these

*and change those in this sketch. (You could always view this later in yourresource management).

* 6.Copy the contents of private key to 'aws_private_key' variable.

* NOTE: Each line must be added with '\n' and quoted with " " tobe parsed successfully.

* 7.Using pycert to convert certificate to header file by running

* $python ../../../tools/pycert/pycert.py convert -c local_cert -l LOCAL_CERT_LEN214900e9fd-certificate.pem.crt.txt

* This should create an certificates.h with variable local_cert.

* 8.Close and reopen this sketch to load certificates.h

* 9.Compile and run

#include "certificates.h"

#define WLAN_SSID "yourSSID"

#define WLAN_PASS "yourPass"

#define MQTT_TX_BUFSIZE 1024

#define MQTT_RX_BUFSIZE 1024

int ledPin = PA15;

AdafruitMQTT mqtt;

//======================================================

#define AWS_IOT_MQTT_HOST "A1B0KY2Z6UVZ7R.iot.us-west-2.amazonaws.com"

#define AWS_IOT_MQTT_PORT 8883

#define AWS_IOT_MQTT_CLIENT_ID "led"

#define AWS_IOT_MY_THING_NAME "led"

//======================================================

#define AWS_IOT_MQTT_TOPIC "$aws/things/"AWS_IOT_MY_THING_NAME "/shadow/update"

#define SHADOW_PUBLISH_STATE_OFF "{ \"state\":{\"reported\": { \"status\": \"OFF\" } } }"

#define SHADOW_PUBLISH_STATE_ON "{ \"state\":{\"reported\": { \"status\": \"ON\" } } }"

const char aws_private_key[] =

"-----BEGIN RSA PRIVATE KEY-----\n"

"Your Key contents line 1 with newlineand quoted\n"

"Quote each of your key's lines likethis example\n"

"-----END RSA PRIVATE KEY-----";

/**************************************************************************/

/*!

@brief Disconnect handler forMQTT broker connection

/**************************************************************************/

void disconnect_callback(void)

{

Serial.println();

Serial.println("-----------------------------");

Serial.println("DISCONNECTEDFROM MQTT BROKER");

Serial.println("-----------------------------");

Serial.println();

}

/**************************************************************************/

/*!

@brief The setup function runsonce when the board comes out of reset

/**************************************************************************/

void setup()

{

pinMode(ledPin, OUTPUT);

Serial.begin(115200);

// Wait for the Serial Monitor to open

while (!Serial)

{

/* Delay required to avoid RTOS task switching problems*/

delay(1);

}

Serial.println("AWS IOT Example\r\n");

// Print all software versions

Feather.printVersions();

while ( !connectAP() )

{

delay(500); // delay between each attempt

}

// Connected: Print network info

Feather.printNetwork();

// Tell the MQTT client to auto print error codes andhalt on errors

mqtt.err_actions(true, true);

// Set ClientID

mqtt.clientID(AWS_IOT_MQTT_CLIENT_ID);

mqtt.setBufferSize(MQTT_TX_BUFSIZE, MQTT_RX_BUFSIZE);

// Set the disconnect callback handler

mqtt.setDisconnectCallback(disconnect_callback);

// default RootCA include certificate to verify AWS

Feather.useDefaultRootCA(true);

// Setting Indentity with AWS Private Key &Certificate

mqtt.tlsSetIdentity(aws_private_key, local_cert, LOCAL_CERT_LEN);

// Connect with SSL/TLS

Serial.printf("Connecting to" AWS_IOT_MQTT_HOST " port %d ... ", AWS_IOT_MQTT_PORT);

mqtt.connectSSL(AWS_IOT_MQTT_HOST, AWS_IOT_MQTT_PORT);

Serial.println("OK");

Serial.print("Subscribing to " AWS_IOT_MQTT_TOPIC " ... ");

mqtt.subscribe(AWS_IOT_MQTT_TOPIC, MQTT_QOS_AT_MOST_ONCE,subscribed_callback); // Will halted if anerror occurs

Serial.println("OK");

// Message to user

Serial.print("Enter '0' or '1' to updatefeed: ");

}

/**************************************************************************/

/*!

@brief This loop function runsover and over again

/**************************************************************************/

void loop()

{

// Get input from user '0' to off, '1' to update feed

if ( Serial.available())

{

char c = Serial.read();

// echo

Serial.println(c);

Serial.print("Enter '0' or '1' to updatefeed: ");

//Serial.print("Publishing to "AWS_IOT_MQTT_TOPIC " ... ");

if ( c == '0' )

{

mqtt.publish(AWS_IOT_MQTT_TOPIC,SHADOW_PUBLISH_STATE_OFF, MQTT_QOS_AT_LEAST_ONCE); // Will halted if an error occurs

}else if ( c == '1' )

{

mqtt.publish(AWS_IOT_MQTT_TOPIC, SHADOW_PUBLISH_STATE_ON,MQTT_QOS_AT_LEAST_ONCE); // Will halted if anerror occurs

}else

{

// do nothing

}

delay(5000);

}

/**************************************************************************/

/*!

@brief MQTT subscribe eventcallback handler

@param topic The topic causing this callback to fire

@param message The new value associated with 'topic'

@note 'topic' and 'message' areUTF8Strings (byte array), which means

they are not null-terminated like C-style strings. You can

access its data and len using .data & .len, although there is

also a Serial.print override to handle UTF8String data types.

/**************************************************************************/

void subscribed_callback(UTF8String topic,UTF8String message)

{

if ( 0 ==memcmp(SHADOW_PUBLISH_STATE_OFF, message.data, message.len) )

{

digitalWrite(ledPin, LOW);

}

if ( 0 ==memcmp(SHADOW_PUBLISH_STATE_ON, message.data, message.len) )

{

digitalWrite(ledPin, HIGH);

}

/**************************************************************************/

/*!

@brief Connect to defined AccessPoint

/**************************************************************************/

bool connectAP(void)

{

// Attempt to connect to an AP

Serial.print("Please wait while connecting to: '" WLAN_SSID "' ... ");

if (Feather.connect(WLAN_SSID, WLAN_PASS) )

{

Serial.println("Connected!");

}

else

{

Serial.printf("Failed! %s(%d)", Feather.errstr(), Feather.errno());

Serial.println();

}

Serial.println();

return Feather.connected();

}

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