feather-th-azure-iot

An internet-connected temperature and humidity monitor for 3D printer enclosures based on the Adafruit Feather TFT ESP32-S3 board and AHT20 breakout sensor.

Code will be written in CircuitPython, and cloud functionality will run through Microsoft Azure, with an emphasis on their low- and no-cost service tiers.

I created this project both to learn more about CircuitPython as well as Azure's IOT services. (Disclosure: I work for Microsoft, but this project is in no way sponsored or endorsed by the company.)

Feature planning & roadmaps will be maintained in this repo's Issues.

Requirements

• Firmware: CircuitPython v8.x for ESP32-S3 TFT PSRAM (currently in alpha)
• Python Libraries:
  • Adafruit CircuitPython library bundle for v8.x (currently in alpha)
  • Adafruit_CircuitPython_AzureIoT library

Software Configuration

Configure the device's behavior by modifying the variables under the # Configuration comment immediately following the import statements.

Variable	Description
delay	The amount of time to wait between sensor readings, in seconds
temp_warning_c	The minimum temperature, in Celcius, at which a warning status will be triggered. Values less than this number will be considered OK. When the temperature is in a warning status, both the Celcius and Fahrenheit will be displayed in yellow.
temp_critical_c	The minimum temperature, in Celcius, which should be considered critical. When the temperature is in a critical status, both the Celcius and Fahrenheit will be displayed in red.
humid_warning	The minimum relative humidity at which a warning status will be triggered. Values less than this number will be considered OK. When the humidity is in a warning status, the relative humidity will be displayed in yellow.
humid_critical	The minimum relative humidity which should be considered critical. When the humidity is in a critical status, the relative humidity will be displayed in red.

Secret Configuration

Wifi connection code uses CircuitPython's secrets.py convention, as shown in this project. To avoid accidentally saving credentials in GitHub, I've added the file to .gitignore.

Create your own secrets.py file in the root of the file system. It needs to contain a dictionary with the SSID. Copy the code below into your new file and populate it with the correct values for your environment.

Note: If you want to use the device in offline-only mode, create the secrets.py file with an empty dictionary or comment out the line that sets ssid.

secrets = {
    'ssid' : 'your-ssid-here',
    'password' : 'your-password-here'
}

Status LED

The onboard NeoPixel is used as an indicator of overall status.

Color	Indication
Red	One or both sensor values are in a Critical status.
Yellow	One or both sensor values are in a Warning status
Green	All sensor values are OK