a MQTT Demo that Connect ESP32 to Azure Cloud

Table of Contents

• Introduction
• Part 1: Prerequisites
• Part 2: Prepare your iothub
• Part 3: SDK and Tools Preparation
• Part 4: Configuring and building
• Part 5: Result shows
• TroubleShoot

Introduction

ESP32 is one of gorgeous ioT device that can interface with other systems to provide Wi-Fi and Bluetooth functionality through the SPI / SDIO or I2C / UART interfaces.for more details, click https://espressif.com/en/products/hardware/esp32/overview

Azure cloud is one of wonderful cloud that could collect data from lot device or push data to lot device,for more details, click https://www.azure.cn/home/features/iot-hub/

Aim:

This page would guide you connecting your device(ESP32 or lot device with ESP32) to Azure by MQTT protocol, and then send data to Azure,receive message from Azure.Main workflow:

https://github.com/ustccw/RepoForShareData/blob/master/Microsoft/AzureData/Photos/ESP32AzureWorkflow.png

Part 1: Prerequisites

• ubuntu environment for building your demo.
• ESP32 device for running the demo.
  https://github.com/ustccw/RepoForShareData/blob/master/Microsoft/AzureData/Photos/ESP32-DevKitC.png

Part 2: Prepare your iothub

follow the guide: https://github.com/ustccw/RepoForShareData/blob/master/Microsoft/AzureData/start_Iothub.docx you would get an iothub login connect string like that:

HostName=yourname-ms-lot-hub.azure-devices.cn;SharedAccessKeyName=iothubowner;SharedAccessKey=zMeLQ0JTlZXVcHBVOwRFVmlFtcCz+CtbDpUPBWexbIY=

Part 3: SDK and Tools Preparation

3.1 iothub-explorer install

The iothub-explorer tool enables you to provision, monitor, and delete devices in your IoT hub. It runs on any operating system where Node.js is available.

• Download and install Node.js from here. https://nodejs.org/en/
• From a command line (Command Prompt on Windows, or Terminal on Mac OS X), execute the following:

    npm install -g iothub-explorer
  

if success, you can get version information like:

$ node -v
v6.9.5
$ iothub-explorer -V
1.1.6

if failed,please click http://thinglabs.io/workshop/esp8266/setup-azure-iot-hub/

after finished:

then you can use your iothub-explorer to manager your iot-device.click https://github.com/ustccw/RepoForShareData/blob/master/Microsoft/AzureData/iothub-explorer

login with: iothub login connect string that gets from Part 2

then you can get one device connect string after you create one device like that:

"HostName=esp-hub.azure-devices.net;DeviceId=yourdevice;SharedAccessKey=L7tvFTjFuVTQHtggEtv3rp+tKEJzQLLpDnO0edVGKCg=";

keep this device connect string in mind.

3.2 SDK get

you can get AZURE-SDK from https://github.com/ustccw/AzureESP32
this SDK can implement that connect ESP32 to Azure by MQTT protocol.
you can get IDF-SDK from https://github.com/espressif/esp-idf
this SDK can make ESP32 work well

3.3 Compiler get

follow the guide: http://esp-idf.readthedocs.io/en/latest/get-started/linux-setup.html

Part 4: Configuring and building

4.1 Update Variables

/examples/project_template/user/iothub_client_sample_mqtt.c

Update the connectionString variable to the device-specific connection string you got earlier from the Setup Azure IoT step:

static const char* connectionString = '[azure connection string]'

The azure connection string contains Hostname, DeviceId, and SharedAccessKey in the format:

"HostName=<host_name>;DeviceId=<device_id>;SharedAccessKey=<device_key>"

4.2 config your Wifi

make menuconfig

choose example configuration to set Wifi SSID and Password!

4.3 build your demo and flash to ESP32

$make flash

if failed,try:

• make sure that ESP32 had connect to PC by serial port
• make sure you flash to correct serial port
• try type command:

  sudo usermod -a -G dialout $USER

Part 5: Result shows

login iothub-explorer,and monitor events:

iothub-explorer monitor-events AirConditionDevice_001 --login 'HostName=youriothub-ms-lot-hub.azure-devices.cn;SharedAccessKeyName=iothubowner;SharedAccessKey=zMeLQ0JTlZXVcHBVOwRFVmlFtcCz+CtbDpUPBWexbIY='

• restart ESP32 after bin had flashed,you would see the ESP32 send data to lothub-explorer by minicom,and iothub-explorer would receive data!
• At the same time,you can send message to ESP32 by iothub-explorer until you send a quit message

TroubleShoot

• close some firewall settings
• build failed,try:
  • git submodule init
  • git submodule update
  • export your compiler path
  • export your SDK path
  • get start with http://espressif.com/en/support/download/documents?keys=&field_type_tid%5B%5D=13
• make sure you had input correct device connect-string which get from Part 3