An Azure IoT Hub Connected Telegraph based on an ESP8266.

Part of my talk "A Short History of IoT" at Notts Techfast 27/08/20.

Instructions

• Add the following to the Additional Boards URLs;

  http://arduino.esp8266.com/stable/package_esp8266com_index.json

• Install the ESP8266 board from the Board Manager

• Set your board to any compatible ESP8266. e.g. Generic ESP8266

• Set your port to the relevant port for the device. e.g. COM3

• Add the following Microsoft libraries to your Arduino IDE

  • AzureIoTHub
  • AzureIoTProtocol_HTTP
  • AzureIoTProtocol_MQQT
  • AzureIoTUtility
  • ArduinoJSON (by Benoit Blanchon)

• Fill in the relevant details in the iot_configs.h file to configure the solution

• You will need to copy the platform.local.txt file to (replace with latest version number);

  %localappdata%\Arduino15\packages\esp8266\hardware\esp8266\2.7.4

• Create an IoT Hub and add a new device. Then copy it's primary connection string to use in iot_configs.h

• Due to a bug in the ESP8266 platform, you will to;

  • Open

  %localappdata%\Arduino15\packages\esp8266\hardware\esp8266\2.7.4\cores\esp8266\Arduino.h

  • Comment out the following line (add a // at the start) (currently line 137);

  #define round(x) ((x)>=0?(long)((x)+0.5):(long)((x)-0.5))

Notes

• The esp8266_sample_init is found in the AzureIoTUtility library in the esp8266/sample_init.cpp

  • This function sets up the Serial Port to a Baud Rate of 115200.

  • This function also initialises the Wi-Fi and uses "pool.ntp.org" and "time.nist.gov" to get the latest time.

  • Getting the time from the NTP can take some time to complete and results in the following message more than 20 times before the IoT Hub connects;

    Fetching NTP epoch time failed! Waiting 2 seconds to retry.

• The normal Serial Monitor log at startup will look something like the following

  Attempting to connect to SSID: xxxxxxxx
  
  connected with xxxxxxxx, channel 6
  dhcp client start...
  scandone
  state: 5 -> 2 (b0)
  ..state: 5 -> 0 (2)
  reconnect
  scandone
  state: 0 -> 2 (b0)
  state: 2 -> 3 (0)
  state: 3 -> 5 (10)
  add 0
  aid 7
  cnt 
  
  connected with xxxxxxx, channel 6
  dhcp client start...
  ip:192.168.1.189,mask:255.255.255.0,gw:192.168.1.254
  .
  Connected to wifi
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  pm open,type:2 0
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetching NTP epoch time failed! Waiting 2 seconds to retry.
  Fetched NTP epoch time is: 1598277023
  Creating IoTHub Device handle
  
  

References

Original Source based on: https://www.instructables.com/id/Morse-Code-Decoder/

Original IoT Code taken from Microsoft Azure IoT Samples for ESP8266: https://github.com/Azure/azure-iot-arduino