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Application Note below on how to connect to AWS using eS-Wifi modules and IWIN AT commands.

Amazon AWS (MQTT) IoT Cloud Setup :

Wi-Fi Connectivity Python Demo  Example

1 Scope

The  eS-WiFi serial to Wi-Fi module family simplifies cloud connectivity by using the Inventek, IWIN AT Command Set to connect a device to the AWS IoT cloud. This provides a detail description of how to:

  1. Setup an AWS account
  2. Modify the Inventek firmware to connect to your AWS account
  3. Run either a “C” project or Python to connect to the AWS cloud
  4. Control a thermistor and some GPIO push buttons

AWS Application Note

Amazon Web Services user interface for Thermostat Demo

2 AWS IoT Description

The Amazon AWS IoT service enables secure, bidirectional communication between IoT devices, sometimes referred to as Internet-connected things or simply things (sensors, actuators, devices, applications, etc.), and the cloud over MQTT.

Things are authenticated using AWS IoT service-provided X.509 certificates. Once a certificate is provisioned and activated it can be installed on a thing. The thing will then use that certificate to send all requests to AWS MQTT. Authorization is controlled by JSON policy files that allow you to specify which resources a specific device (certificate) may access.  Inventek’s eS-WiFi Demo program incorporates a firmware customization feature to program the required certificated on a device.

3 AWS IoT Setup

For complete information on getting started using the AWS IoT service, see:

The following steps summarize what a user should do to get started using the AWS IoT service with a device:

  1. Go to the AWS IoT service by clicking on or entering  in a browser.
  2. Create an AWS account by clicking on “Get started with AWS IoT
  3. Sign in to the AWS Management Console by clicking on or navigating to and then clicking on Sign in to the AWS Console.
  4. In the webpage that opens, select US East (N. Virginia) as the server region for management console use during the AWS IoT beta:

Amazon Web Services user interface for selecting East of USA location

5. In the Internet of Things column, click AWS IoT  to start using the management console

internet of things connect devices to cloud

6. In the webpage that opens, click Get started:

7. In the AWS IoT management console webpage:

  • Click Create a resource.
  • Click Create a thing, enter the name of the thing (for example, lightbulb)
  • Then click Create.

Amazon Web Services user interface for Internet of Things

8. Click View thing in order to connect a device.

Amazon Web Services user interface for Internet of Things view option

9. Click Connect a Device.

Amazon Web Services user interface for IoT resources option

10. Click Embedded C as the supported SDK and then click Generate Certificate and Policy.

Amazon Web Services user interface for Internet of Things connect a device Embedded C option

Sequentially click on the Download Public Key, Download Private Key, and Download Certificate links and for each click Save File, OK, navigate to the directory where the credentials should be stored, and then click Save. Also, Download the Root CA:

    1. Download the Root CA cert here:
    2. Save it with the .pem file extension

4 eS-WiFi Module Setup

After you have completed your AWS account setup, you need to modify the Inventek firmware to add your particular AWS account credentials.  You need the following files that you can download from the Inventek website:

  1. es-Wifi Demo Program (PC program)
  2. ISM43362 Firmware image or later
  3. or ISM43340 Firmware image or later

4.1 Creating the AWS eS-WiFi Firmware Image for your account

  1. Create a folder on your PC with the following files:
    1. ISM43362_M3G_L44_C3.5.2.0.bin  (beta)
    2. RootCA. pem
    3. AWS-Certificate.crt
    4. AWS-Private.pem.key (Downloaded in Step F above)
  2. Open the eS-WiFi Demo Program to create the Image. Select
    1. AWS Certs

Inventek Systems eS_WiFi Demo user interface

Then Selects Menu—>Firmware —>Customize —> AWS Certs —> Run

Inventek Systems eS_WiFi Demo user interface Menu Firmware option

Go to the Folder in from Step 1 and select the files in the following order:

  1. Firmware
  2. Root CA
  3. Certificate
  4. Private Key

Note: You can also customize your logo/Fav icon. Needs to be less than 4K in size

The eS-WiFi demo program will automatically create a new firmware image that you can use to re-flash your evaluation board.

  1. Plug your evb into the PC USB port. (see user manual if you have not already installed the FTDi drivers)
  2. Select Menu—> Firmware —> Update to program the new firmware Image
  3. Point to the newly created *.bin in your AWS folder
  4. Your module is now updated with your firmware that is setup to connect to your AWS account

Inventek Systems eS_WiFi Demo user interface Menu Firmware Update option

 Python Script to Connect to AWS using IWIN AT Commands

Now that you have an AWS account and the eS-WiFi module has been updated with your account credentials, this section shows you how to connect to the AWS cloud using either a Python Script or “C” code”.

5 AWS Python Thermostat Script

Download the IWIN AWS Thermostat Demo  Python script to your PC.

On the Inventek ISM43362 or ISM43340 evaluation boards there is a Thermistor and two blue GPIO Buttons that are used by the Python script. The demo will connect you to the Amazon AWS cloud, and present the temperature as well as your last set points for the Thermostat. Using AWS shadow you can see temperature and current thermostat settings. For real time viewing of data on the AWS cloud use the MQTT client detailed below.

  • Thermistor = Temperature on AWS
  • Button #1: Sets Thermostat upper limit
  • Button # 2: Sets Thermostat Lower limit
  • Press #1 & #2 : Program exits

ISM4319-M3-EVB-U with description

Portable Python Software

Locate the following section of the code in the Python script and make the changes to configure your network and AWS certificates:

#Network Configuration Method
useSoftAP = 0               #Join using, 0 = Cx commands, 1 = A0 (SoftAP)
    #Local Network Setup
SSID = “ssid”                   #SSID of AP
PSWD = “password”               #Password of AP
SEC=”4″                         #Security type of AP: 0-Open, 1-WEP, 2-WPA, 3-WPA2-AES, 4-WPA2-Mixed
DHCP=”1″                        #Get IP address for DHCP, 0-No, 1-Yes
    #Socket/Protocol Setup
SOCKET = “0”                    #Select Socket 0-3
PROTOCOL=”4″                    #TCP=0, UDP=1, UDP-Lite=2 TCP-SSL=3(Hercules doesn’t support), 4-MQTT
    #MQTT Setup
PBTOPIC=”$aws/things/<Thing_name>/shadow/update”  #Publish topic
SBTOPIC=”$aws/things/<Thing_name>/shadow/update/accepted”  #Subscribe topic
MQTTMODE = “2”                  #Mode 0-None, 1-User Name/Password, 2-Certificates(AWS IoT)
    #TCP Keep-Alive
TTI = 3000                      #Time-To-Idle (ms)
    #AWS IoT
deviceID = “<AWS_ID>”                                   #AWS Device Id
remoteURL = deviceID + “”   #AWS Location URL
    #Client Mode
useDNS = 1
remoteIP = “”       #Remote Server IP address (use with AD Direct Mode)
remotePort = “8883”             #Remote TCP port
  1. Locate the “Local Network Setup”
    1. Change “ssid” to the name of your Access Point
    2. Change “password” to the password of your Access Point
  2. Locate the “MQTT Setup”
    1. In the PBTOPIC change “<Thing_name>” to the name of your thing
    2. In the SBTTOPIC change “<Thing_name>” to the name of your thing
  3. Locate the “AWS IoT”
    1. Change “<AWS_ID>” to your AWS device ID. This is located in the Rest API endpoint :HTTPS://A3SXXXXXXXXXXX
    2. Change the URL location to match the location of where you created your thing ex.”” to “”
  4. Locate the “Client Mode”
    1. Check the remote Port matches the port for your thing

Note: On the AWS IoT Webpage, Click on the desired thing (i.e. Temp), Then Click the Details tab for URL and Topic Information. The topic information in s

Amazon Web Services user interface for Control Panel

At this point you have completed your basic connection to the Amazon AWS cloud. You have connected your Thermostat to the Amazon cloud and published some basic GPIO controls as well as Temperature. The next step is to work on creating your controls and database using the AWS tools available.

To view your AWS cloud connected product real time, you can use the MQTT.fx tool on your PC as detailed below:

6 Verify MQTT Subscribe and Publish

The steps in this section show you how to verify you can use your certificate to communicate with AWS IoT over MQTT. You will use an MQTT client to subscribe and publish to an MQTT topic.

This guide assumes you are using MQTT.fx, an MQTT client written in Java based on Eclipse Paho. You can install it from Download MQTT.fx

6.1 Configure MQTT.fx

To configure MQTT.fx, open the app and choose the gear icon at the top of the page.

Inventek Systems eS_WiFi Demo project connection profile general settings

Type a profile name. In Broker Address, type your account-specific AWS IoT endpoint URL. Use the describe-endpoint CLI command to find your account-specific AWS IoT endpoint URL. In Broker Port, type 8883, as shown here:

Inventek Systems eS_WiFi Demo project connection profile self signed certificate setting

Choose the SSL/TLS button to view the SSL/TLS settings page. Type the paths to your private key, certificate, and root CA certificate as shown here:

Inventek Systems eS_WiFi Demo project subscribe setting

Choose the OK to save your settings, and then choose Connect to connect to AWS IoT.

6.2 Subscribe to an MQTT Topic

Choose Subscribe and the Subscribe page will be displayed. Type my/topic in the text box, from the drop-down list, select QoS 0, and then choose Subscribe.

publish option for Inventek Systems eS_WiFi Demo project

6.3 Publish to an MQTT Topic

Choose the Publish link and the publish page will be displayed. Type my/topic in the text box, and then type some text in the message area. From the drop-down box, choose QoS 0, and then choose Publish.

Inventek Systems eS_WiFi Demo project

Choose Subscribe to display the Subscribe page. You should see the message has been received.

United States Inventek Systems $$ 2016-01-07T16:09:24-05:00 2020-02-17T13:20:44-05:00