Skip to main content
PyPortal Air Quality Display

PyPortal Air Quality Display

Image for user johnpark
by John Park
published March 13, 2019, last edited January 22, 2025
posted in Internet of Things - IOT/ Wireless LCDs & Displays/ Graphic TFTs Programming/ MicroPython / CircuitPython
Save Download
33
Beginner
Project guide
⚡️ 1

Overview

wireless_airIMG_4431_2k.jpg

With the PyPortal air quality display stuck to your fridge, you can keep track of the quality of the air you breathe.

Using CircuitPython, this project queries the AirNow site API to find out the current air quality index for your location and displays it along with an informative color.

3D printed case and magnetic backing allow you to mount it to your fridge or other ferrous metal surface.

Note that the Air Quality information used in this tutorial is from https://airnow.gov/ which only provides information for the United States and then only certain geographic areas (by postal Zip Code). If you wish to use this project in other areas, you may have to adapt the project to another data source which is not covered in this guide.
Front view of a Adafruit PyPortal - CircuitPython Powered Internet Display with a pyportal logo image on the display.
PyPortal, our easy-to-use IoT device that allows you to create all the things for the “Internet of Things” in minutes. Make custom touch screen interface...
guides with product
$54.95
In Stock
Add to Cart
5V 2A Switching Power Supply with USB-A Connector
Our 5V 2A USB power adapter is the perfect choice for powering single-board computers like Raspberry Pi, BeagleBone, or anything else that's power-hungry!This adapter was...
$7.95
In Stock
Add to Cart
USB Cable with Type A and Micro B ends
This is your standard USB A-Plug to Micro-USB cable. It's 2 meters long so you'll have plenty of cord to work with for those longer extensions.
$4.95
In Stock
Add to Cart

Additional Tools & Materials

You may want to create the optional mounting case for your PyPortal Air Quality Display. For this you'll need:

If you don't have access to a 3D printer you can optionally use an online service such as 3D Hubs to have it printed for you on demand.

Magnetic Pin Back
These magnetic pin backs have two pieces: a metal bar with adhesive strip and a plastic piece with two strong rare-earth magnets. Affix the metal bar to your FLORA projects-- it's...
$1.95
In Stock
Add to Cart
Black Nylon Screw and Stand-off Set with M2.5 Threads, kit box
Totaling 380 pieces, this M2.5 Screw Set is a must-have for your workstation. You'll have enough screws, nuts, and hex standoffs to fuel your maker...
guides with product
$16.95
In Stock
Add to Cart

Page last edited March 08, 2024

Text editor powered by tinymce.

Install CircuitPython

CircuitPython is a derivative of MicroPython designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the CIRCUITPY "flash" drive to iterate.

The following instructions will show you how to install CircuitPython. If you've already installed CircuitPython but are looking to update it or reinstall it, the same steps work for that as well!

Set up CircuitPython Quick Start!

Follow this quick step-by-step for super-fast Python power :)

circuitpython_pyportal-uf2.png

Click the link above to download the latest version of CircuitPython for the PyPortal.

Download and save it to your desktop (or wherever is handy).

circuitpython_PyPortalResetNeoPIxel.jpg

Plug your PyPortal into your computer using a known-good USB cable.

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync.

Double-click the Reset button on the top in the middle (magenta arrow) on your board, and you will see the NeoPixel RGB LED (green arrow) turn green. If it turns red, check the USB cable, try another USB port, etc. Note: The little red LED next to the USB connector will pulse red. That's ok!

If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!

circuitpython_PyPortal_PORTALBOOT.png
circuitpython_PyPortal_PORTALBOOT.png
circuitpython_PyPortal_Drag_UF2.png

You will see a new disk drive appear called PORTALBOOT.

Drag the adafruit-circuitpython-pyportal-<whatever>.uf2 file to PORTALBOOT.

circuitpython_PyPortalCIRCUITPY.png

The LED will flash. Then, the PORTALBOOT drive will disappear and a new disk drive called CIRCUITPY will appear.

If you haven't added any code to your board, the only file that will be present is boot_out.txt. This is absolutely normal! It's time for you to add your code.py and get started!

That's it, you're done! :)

PyPortal Default Files

Click below to download a zip of the files that shipped on the PyPortal or PyPortal Pynt.

Page last edited March 08, 2024

Text editor powered by tinymce.

PyPortal CircuitPython Setup

To use all the amazing features of your PyPortal with CircuitPython, you must first install a number of libraries. This page covers that process.

Adafruit CircuitPython Bundle

Download the Adafruit CircuitPython Library Bundle. You can find the latest release here:

Download the adafruit-circuitpython-bundle-*.x-mpy-*.zip bundle zip file where *.x MATCHES THE VERSION OF CIRCUITPYTHON YOU INSTALLED, and unzip a folder of the same name. Inside you'll find a lib folder. You have two options:

  • You can add the lib folder to your CIRCUITPY drive. This will ensure you have all the drivers. But it will take a bunch of space on the 8 MB disk
  • Add each library as you need it, this will reduce the space usage but you'll need to put in a little more effort.

At a minimum we recommend the following libraries, in fact we more than recommend. They're basically required. So grab them and install them into CIRCUITPY/lib now!

  • adafruit_esp32spi - This is the library that gives you internet access via the ESP32 using (you guessed it!) SPI transport. You need this for anything Internet
  • adafruit_requests - This library allows us to perform HTTP requests and get responses back from servers. GET/POST/PUT/PATCH - they're all in here!
  • adafruit_connection_manager - used by adafruit_requests.
  • adafruit_pyportal - This is our friendly wrapper library that does a lot of our projects, displays graphics and text, fetches data from the internet. Nearly all of our projects depend on it!
  • adafruit_portalbase - This library is the base library that adafruit_pyportal library is built on top of.
  • adafruit_touchscreen - a library for reading touches from the resistive touchscreen. Handles all the analog noodling, rotation and calibration for you.
  • adafruit_io - this library helps connect the PyPortal to our free datalogging and viewing service
  • adafruit_imageload - an image display helper, required for any graphics!
  • adafruit_display_text - not surprisingly, it displays text on the screen
  • adafruit_bitmap_font - we have fancy font support, and its easy to make new fonts. This library reads and parses font files.
  • adafruit_slideshow - for making image slideshows - handy for quick display of graphics and sound
  • neopixel - for controlling the onboard neopixel
  • adafruit_adt7410 - library to read the temperature from the on-board Analog Devices ADT7410 precision temperature sensor (not necessary for Titano or Pynt)
  • adafruit_bus_device - low level support for I2C/SPI
  • adafruit_fakerequests - This library allows you to create fake HTTP requests by using local files.

Page last edited March 08, 2024

Text editor powered by tinymce.

Create Your settings.toml File

CircuitPython works with WiFi-capable boards to enable you to make projects that have network connectivity. This means working with various passwords and API keys. As of CircuitPython 8, there is support for a settings.toml file. This is a file that is stored on your CIRCUITPY drive, that contains all of your secret network information, such as your SSID, SSID password and any API keys for IoT services. It is designed to separate your sensitive information from your code.py file so you are able to share your code without sharing your credentials.

CircuitPython previously used a secrets.py file for this purpose. The settings.toml file is quite similar.

Your settings.toml file should be stored in the main directory of your CIRCUITPY drive. It should not be in a folder.

CircuitPython settings.toml File

This section will provide a couple of examples of what your settings.toml file should look like, specifically for CircuitPython WiFi projects in general.

The most minimal settings.toml file must contain your WiFi SSID and password, as that is the minimum required to connect to WiFi. Copy this example, paste it into your settings.toml, and update:

  • your_wifi_ssid
  • your_wifi_password
Download File
Copy Code 
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"

Many CircuitPython network-connected projects on the Adafruit Learn System involve using Adafruit IO. For these projects, you must also include your Adafruit IO username and key. Copy the following example, paste it into your settings.toml file, and update:

  • your_wifi_ssid
  • your_wifi_password
  • your_aio_username
  • your_aio_key
Download File
Copy Code 
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME = "your_aio_username"
ADAFRUIT_AIO_KEY = "your_aio_key"

Some projects use different variable names for the entries in the settings.toml file. For example, a project might use ADAFRUIT_AIO_ID in the place of ADAFRUIT_AIO_USERNAME. If you run into connectivity issues, one of the first things to check is that the names in the settings.toml file match the names in the code.

Not every project uses the same variable name for each entry in the settings.toml file! Always verify it matches the code.

settings.toml File Tips

Here is an example settings.toml file.

Download File
Copy Code 
# Comments are supported
CIRCUITPY_WIFI_SSID = "guest wifi"
CIRCUITPY_WIFI_PASSWORD = "guessable"
CIRCUITPY_WEB_API_PORT = 80
CIRCUITPY_WEB_API_PASSWORD = "passw0rd"
test_variable = "this is a test"
thumbs_up = "\U0001f44d"

In a settings.toml file, it's important to keep these factors in mind:

  • Strings are wrapped in double quotes; ex: "your-string-here"
  • Integers are not quoted and may be written in decimal with optional sign (+1, -1, 1000) or hexadecimal (0xabcd).
    • Floats, octal (0o567) and binary (0b11011) are not supported.
  • Use \u escapes for weird characters, \x and \ooo escapes are not available in .toml files
    • Example: \U0001f44d for 👍 (thumbs up emoji) and \u20ac for € (EUR sign)
  • Unicode emoji, and non-ASCII characters, stand for themselves as long as you're careful to save in "UTF-8 without BOM" format
adafruit_products_dotToml.jpg

 

 

When your settings.toml file is ready, you can save it in your text editor with the .toml extension.

Accessing Your settings.toml Information in code.py

In your code.py file, you'll need to import the os library to access the settings.toml file. Your settings are accessed with the os.getenv() function. You'll pass your settings entry to the function to import it into the code.py file.

Download File
Copy Code 
import os

print(os.getenv("test_variable"))
adafruit_products_tomlOutput.jpg

In the upcoming CircuitPython WiFi examples, you'll see how the settings.toml file is used for connecting to your SSID and accessing your API keys.

Page last edited March 08, 2024

Text editor powered by tinymce.

Internet Connect!

Connect to WiFi

OK, now that you have your settings.toml file set up - you can connect to the Internet.

To do this, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.

Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory examples/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.

Your CIRCUITPY drive should now look similar to the following image:

CIRCUITPY

Update to CircuitPython 9.2.x or later to use this example.
Download Project Bundle
Copy Code 
# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

from os import getenv
import board
import busio
from digitalio import DigitalInOut
import adafruit_connection_manager
import adafruit_requests
from adafruit_esp32spi import adafruit_esp32spi

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 SPI webclient test")

TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"


# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an AirLift Shield:
# esp32_cs = DigitalInOut(board.D10)
# esp32_ready = DigitalInOut(board.D7)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

# If you have an externally connected ESP32:
# NOTE: You may need to change the pins to reflect your wiring
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)

if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))

for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))

print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print(
    "IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com"))
)
print("Ping google.com: %d ms" % esp.ping("google.com"))

# esp._debug = True
print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print("-" * 40)
print(r.text)
print("-" * 40)
r.close()

print()
print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print("-" * 40)
print(r.json())
print("-" * 40)
r.close()

print("Done!")
View on GitHub

And save it to your board, with the name code.py.

Don't forget you'll also need to create the settings.toml file as seen above, with your WiFi ssid and password.

In a serial console, you should see something like the following. For more information about connecting with a serial console, view the guide Connecting to the Serial Console.

Copy Text 
>>> import wifitest
ESP32 SPI webclient test
ESP32 found and in idle mode
Firmware vers. 1.7.5
MAC addr: 24:C9:DC:BD:0F:3F
	HomeNetwork             RSSI: -46
	HomeNetwork             RSSI: -76
	Fios-12345              RSSI: -92
	FiOS-AB123              RSSI: -92
	NETGEAR53               RSSI: -93
Connecting to AP...
Connected to HomeNetwork 	RSSI: -45
My IP address is 192.168.1.245
IP lookup adafruit.com: 104.20.39.240
Ping google.com: 30 ms
Fetching text from http://wifitest.adafruit.com/testwifi/index.html
----------------------------------------
This is a test of Adafruit WiFi!
If you can read this, its working :)
----------------------------------------

Fetching json from http://wifitest.adafruit.com/testwifi/sample.json
----------------------------------------
{'fun': True, 'company': 'Adafruit', 'founded': 2005, 'primes': [2, 3, 5], 'pi': 3.14, 'mixed': [False, None, 3, True, 2.7, 'cheese']}
----------------------------------------
Done!

Going over the example above, here's a breakdown of what the program is doing:

  • Initialize the ESP32 over SPI using the SPI port and 3 control pins:
Download File
Copy Code 
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

#...

else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)
  • Get the socket pool and the SSL context, and then tell the adafruit_requests library about them.
Download File
Copy Code 
pool = adafruit_connection_manager.get_radio_socketpool(esp)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(esp)
requests = adafruit_requests.Session(pool, ssl_context)
  • Verify an ESP32 is found, checks the firmware and MAC address
Download File
Copy Code 
if esp.status == adafruit_esp32spi.WL_IDLE_STATUS:
    print("ESP32 found and in idle mode")
print("Firmware vers.", esp.firmware_version)
print("MAC addr:", ":".join("%02X" % byte for byte in esp.MAC_address))
  • Perform a scan of all access points it can see and print out the name and signal strength.
Download File
Copy Code 
for ap in esp.scan_networks():
    print("\t%-23s RSSI: %d" % (ap.ssid, ap.rssi))
  • Connect to the AP we've defined here, then print out the local IP address. Then attempt to do a domain name lookup and ping google.com to check network connectivity. (Note sometimes the ping fails or takes a while; this isn't a big deal.)
Download File
Copy Code 
print("Connecting to AP...")
while not esp.is_connected:
    try:
        esp.connect_AP(ssid, password)
    except OSError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", esp.ap_info.ssid, "\tRSSI:", esp.ap_info.rssi)
print("My IP address is", esp.ipv4_address)
print(
    "IP lookup adafruit.com: %s" % esp.pretty_ip(esp.get_host_by_name("adafruit.com"))
)

Now we're getting to the really interesting part of the example program. We've written a library for web fetching web data, named adafruit_requests. It is a lot like the regular Python library named requests. This library allows you to send HTTP and HTTPS requests easily and provides helpful methods for parsing the response from the server.

  • Here is the part of the example program is fetching text data from a URL.
Download File
Copy Code 
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"  # Further up in the program

# ...

print("Fetching text from", TEXT_URL)
r = requests.get(TEXT_URL)
print('-' * 40)
print(r.text)
print('-' * 40)
r.close()
  • Finally, here the program is fetching some JSON data. The adafruit_requests library will parse the JSON into a Python dictionary whose structure is the same as the structure of the JSON.
Download File
Copy Code 
JSON_URL = "http://wifitest.adafruit.com/testwifi/sample.json"   # Further up in the program

# ...

print("Fetching json from", JSON_URL)
r = requests.get(JSON_URL)
print('-' * 40)
print(r.json())
print('-' * 40)
r.close()

Advanced Requests Usage

Want to send custom HTTP headers, parse the response as raw bytes, or handle a response's http status code in your CircuitPython code?

We've written an example to show advanced usage of the requests module below.

To use with CircuitPython, you need to first install a few libraries, into the lib folder on your CIRCUITPY drive. Then you need to update code.py with the example script.

Thankfully, we can do this in one go. In the example below, click the Download Project Bundle button below to download the necessary libraries and the code.py file in a zip file. Extract the contents of the zip file, open the directory examples/ and then click on the directory that matches the version of CircuitPython you're using and copy the contents of that directory to your CIRCUITPY drive.

Download Project Bundle
Copy Code 
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import os

import adafruit_connection_manager
import board
import busio
from adafruit_esp32spi import adafruit_esp32spi
from digitalio import DigitalInOut

import adafruit_requests

# Get WiFi details, ensure these are setup in settings.toml
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# If you have an AirLift Featherwing or ItsyBitsy Airlift:
# esp32_cs = DigitalInOut(board.D13)
# esp32_ready = DigitalInOut(board.D11)
# esp32_reset = DigitalInOut(board.D12)

spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
radio = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

print("Connecting to AP...")
while not radio.is_connected:
    try:
        radio.connect_AP(ssid, password)
    except RuntimeError as e:
        print("could not connect to AP, retrying: ", e)
        continue
print("Connected to", str(radio.ap_info.ssid, "utf-8"), "\tRSSI:", radio.ap_info.rssi)

# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)

JSON_GET_URL = "https://httpbin.org/get"

# Define a custom header as a dict.
headers = {"user-agent": "blinka/1.0.0"}

print("Fetching JSON data from %s..." % JSON_GET_URL)
with requests.get(JSON_GET_URL, headers=headers) as response:
    print("-" * 60)

    json_data = response.json()
    headers = json_data["headers"]
    print("Response's Custom User-Agent Header: {0}".format(headers["User-Agent"]))
    print("-" * 60)

    # Read Response's HTTP status code
    print("Response HTTP Status Code: ", response.status_code)
    print("-" * 60)
View on GitHub

Your CIRCUITPY drive should now look similar to the following image:

CIRCUITPY

WiFi Manager

The way the examples above connect to WiFi works but it's a little finicky. Since WiFi is not necessarily so reliable, you may have disconnects and need to reconnect. For more advanced uses, we recommend using the WiFiManager class. It will wrap the connection/status/requests loop for you - reconnecting if WiFi drops, resetting the ESP32 if it gets into a bad state, etc.

Here's a more advanced example that shows using the WiFiManager and also how to fetch the current time from a web source.

Download Project Bundle
Copy Code 
# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
from os import getenv
import board
import busio
from digitalio import DigitalInOut
import neopixel
import rtc
from adafruit_esp32spi import adafruit_esp32spi
from adafruit_esp32spi.adafruit_esp32spi_wifimanager import WiFiManager

# Get wifi details and more from a settings.toml file
# tokens used by this Demo: CIRCUITPY_WIFI_SSID, CIRCUITPY_WIFI_PASSWORD
ssid = getenv("CIRCUITPY_WIFI_SSID")
password = getenv("CIRCUITPY_WIFI_PASSWORD")

print("ESP32 local time")

TIME_API = "http://worldtimeapi.org/api/ip"

# If you are using a board with pre-defined ESP32 Pins:
esp32_cs = DigitalInOut(board.ESP_CS)
esp32_ready = DigitalInOut(board.ESP_BUSY)
esp32_reset = DigitalInOut(board.ESP_RESET)

# If you have an externally connected ESP32:
# esp32_cs = DigitalInOut(board.D9)
# esp32_ready = DigitalInOut(board.D10)
# esp32_reset = DigitalInOut(board.D5)

# Secondary (SCK1) SPI used to connect to WiFi board on Arduino Nano Connect RP2040
if "SCK1" in dir(board):
    spi = busio.SPI(board.SCK1, board.MOSI1, board.MISO1)
else:
    spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
esp = adafruit_esp32spi.ESP_SPIcontrol(spi, esp32_cs, esp32_ready, esp32_reset)

"""Use below for Most Boards"""
status_pixel = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.2)
"""Uncomment below for ItsyBitsy M4"""
# status_pixel = dotstar.DotStar(board.APA102_SCK, board.APA102_MOSI, 1, brightness=0.2)
"""Uncomment below for an externally defined RGB LED (including Arduino Nano Connect)"""
# import adafruit_rgbled
# from adafruit_esp32spi import PWMOut
# RED_LED = PWMOut.PWMOut(esp, 26)
# GREEN_LED = PWMOut.PWMOut(esp, 27)
# BLUE_LED = PWMOut.PWMOut(esp, 25)
# status_pixel = adafruit_rgbled.RGBLED(RED_LED, BLUE_LED, GREEN_LED)

wifi = WiFiManager(esp, ssid, password, status_pixel=status_pixel)

the_rtc = rtc.RTC()

response = None
while True:
    try:
        print("Fetching json from", TIME_API)
        response = wifi.get(TIME_API)
        break
    except OSError as e:
        print("Failed to get data, retrying\n", e)
        continue

json = response.json()
current_time = json["datetime"]
the_date, the_time = current_time.split("T")
year, month, mday = [int(x) for x in the_date.split("-")]
the_time = the_time.split(".")[0]
hours, minutes, seconds = [int(x) for x in the_time.split(":")]

# We can also fill in these extra nice things
year_day = json["day_of_year"]
week_day = json["day_of_week"]
is_dst = json["dst"]

now = time.struct_time(
    (year, month, mday, hours, minutes, seconds, week_day, year_day, is_dst)
)
print(now)
the_rtc.datetime = now

while True:
    print(time.localtime())
    time.sleep(1)
View on GitHub

Further Information

For more information on the basics of doing networking in CircuitPython, see this guide:

Page last edited March 08, 2024

Text editor powered by tinymce.

Code PyPortal with CircuitPython

AirNow API Key

We'll be using the US government's site airnow.gov to retrieve the air quality index through its API. In order to do so, you'll need to register for an account and get your API key.

Go to this link and register. Once registered, you'll get an email containing your API key, also known as the "airnow token".

Copy and paste this key into your settings.toml file that is on the root level of your CIRCUITPY drive, so it looks something like this:

Download File
Copy Code 
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
AIRNOW_TOKEN = "XXX0XXXX-0000-0000-0000-XXXXXXXX0000"
Airnow.Gov only provides data for the United States and only for specific postal Zip codes. Please check to ensure data for your area is available. While this guide can be used as a template for using other data sources, changes to do so are not in the scope of this guide and Adafruit cannot assist in changes for other data sources.

Adafruit IO Time Server

In order to get the precise time, our project will query the Adafruit IO Internet of Things service for the time. Adafruit IO is absolutely free to use, but you'll need to log in with your Adafruit account to use it. If you don't already have an Adafruit login, create one here.

If you haven't used Adafruit IO before, check out this guide for more info.

Once you have logged into your account, there are two pieces of information you'll need to place in your settings.toml file: Adafruit IO username, and Adafruit IO key. Head to io.adafruit.com and simply click the View AIO Key link on the left hand side of the Adafruit IO page to get this information.

Then, add them to the settings.toml file like this:

Download File
Copy Code 
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
AIRNOW_TOKEN = "XXX0XXXX-0000-0000-0000-XXXXXXXX0000"
AIO_USERNAME = "your_aio_username"
AIO_KEY = "your_aio_key"

CircuitPython Code

In the embedded code element below, click on the Download Project Bundle button, and save the .zip archive file to your computer.

Then, uncompress the .zip file, it will unpack to a folder named PyPortal_AirQuality.

Copy the contents of the PyPortal_AirQuality directory to your PyPortal CIRCUITPY drive.

wireless_py_airquality_drag.jpg

This is what the final contents of the CIRCUITPY drive will look like:

CIRCUITPY
Download Project Bundle
Copy Code 
# SPDX-FileCopyrightText: 2019 Limor Fried for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
This example will access the twitter follow button API, grab a number like
the number of followers... and display it on a screen!
if you can find something that spits out JSON data, we can display it
"""
import os
import time
import board
from adafruit_pyportal import PyPortal

# Change this to your zip code, not all locations have AQI data. Check
# https://airnow.gov/ to see if there's data available!
LOCATION = "90210"

# Set up where we'll be fetching data from
DATA_SOURCE = "http://www.airnowapi.org/aq/forecast/zipCode/?format=application/json"
# You'll need to get a token from airnow.gov, looks like '4d36e978-e325-11cec1-08002be10318'
DATA_SOURCE += "&zipCode="+LOCATION+"&API_KEY="+os.getenv("AIRNOW_TOKEN")
DATA_LOCATION = [1, "AQI"]

# the current working directory (where this file is)
cwd = ("/"+__file__).rsplit('/', 1)[0]
# Initialize the pyportal object and let us know what data to fetch and where
# to display it
pyportal = PyPortal(url=DATA_SOURCE,
                    json_path=DATA_LOCATION,
                    status_neopixel=board.NEOPIXEL,
                    default_bg=0x000000,
                    text_font=cwd+"/fonts/Helvetica-Bold-100.bdf",
                    text_position=(90, 100),
                    text_color=0x000000,
                    caption_text="Air Quality Index for "+LOCATION,
                    caption_font=cwd+"/fonts/HelveticaNeue-24.bdf",
                    caption_position=(15, 220),
                    caption_color=0x000000,)

while True:
    try:
        value = pyportal.fetch()
        print("Response is", value)
        if 0 <= value <= 50:
            pyportal.set_background(0x66bb6a)  # good
        if 51 <= value <= 100:
            pyportal.set_background(0xffeb3b)  # moderate
        if 101 <= value <= 150:
            pyportal.set_background(0xf39c12)  # sensitive
        if 151 <= value <= 200:
            pyportal.set_background(0xff5722)  # unhealthy
        if 201 <= value <= 300:
            pyportal.set_background(0x8e24aa)  # very unhealthy
        if 301 <= value <= 500:
            pyportal.set_background(0xb71c1c ) # hazardous

    except RuntimeError as e:
        print("Some error occured, retrying! -", e)

    time.sleep(10*60)  # wait 10 minutes before getting again
View on GitHub
If you run into any errors, such as "ImportError: no module named `adafruit_display_text.label`" be sure to update your libraries to the latest release bundle!

How It Works

The PyPortal Air Quality Display has a few steps it takes to provide you with the information you desire!

We'll be displaying the Air Quality Index for Particle Pollution (PM) for fine particles, 2.5 micrometers in diameter or smaller. PM2.5 particles come from all kinds of combustion.

WiFi

First, the program will connect to the WiFi network specified in the secrets.py file.

API Query and JSON

Then, it will send a request to the AirNow URL using your LOCATION United States Zip code specified in the code, as well as your AirNow token from the secrets.py file.

The query looks something like this:

http://www.airnowapi.org/aq/forecast/zipCode/?format=application/json&zipCode=90210&API_KEY=XXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

(where all of those 'x's are your token).

When this query is complete, it returns a JSON file that looks like this:

Download File
Copy Code 
[
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-10 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "O3",
    "AQI": 32,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-10 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "PM2.5",
    "AQI": 33,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-10 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "PM10",
    "AQI": 7,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-10 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "NO2",
    "AQI": 22,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-10 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "CO",
    "AQI": 5,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-11 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "O3",
    "AQI": 29,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-11 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "PM2.5",
    "AQI": 33,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-11 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "PM10",
    "AQI": 9,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-11 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "NO2",
    "AQI": 18,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  },
  {
    "DateIssue": "2019-03-09 ",
    "DateForecast": "2019-03-11 ",
    "ReportingArea": "NW Coastal LA",
    "StateCode": "CA",
    "Latitude": 34.0505,
    "Longitude": -118.4566,
    "ParameterName": "CO",
    "AQI": 6,
    "Category": {
      "Number": 1,
      "Name": "Good"
    },
    "ActionDay": false
  }
]

You can use online code "beautifiers" such as https://codebeautify.org/jsonviewer or http://jsonviewer.stack.hu to get a nice hierarchical view of the data in the JSON file:

wireless_airnowbeauty.png

JSON Traversal

The JSON file is formatted in a way that makes it easy to traverse the hierarchy and parse the data. In it, you'll see keys, such as DateIssue, ReportingArea, ParameterName, and AQI, and their respective values. The key : value pair we care about for the Air Quality Display is the Air Quality Index of particle pollution (PM2.5), or AQI. This is the pair:

  • "AQI" : "33"

In order to fetch this data from the file, we need to be able to describe their locations in the file hierarchically. This is helpful, for example, in differentiating between the 'AQI' in the 'PM2.5' section vs. the 'AQI' in the 'NO2' section. To avoid name clashing we rely on JSON traversal.

In the airquality.py file, you'll see how this is done. For example, the key we want for PM2.5 is found in this hierarchy of the JSON file: [1, "AQI"]

This means there is a sub-tree to the top level of the file indexed [1], which is the second section, as the first is indexed zero. Then, below that level is the 'AQI' key we want.

The value of that key in this case is '33' which is considered to be in the "good" range of particle pollution.

Background

For the background, it displays a solid color based on the current air quality index value. 0-50 is considered good, for example, and has a green background. Here is the full set:

  • 0-50, "good", green
  • 51-100, "moderate", yellow
  • 101-150, "sensitive", orange
  • 151-200 "unhealthy", red
  • 210-300, "very unhealthy", purple
  • 301-500, "hazardous", maroon

Font

The AQI value is displayed as text created with a bitmapped font to overlay on top of the background. The fonts used here are bitmap fonts made from the Helvetica typeface. You can learn more about converting type in this guide.

At the bottom of the screen, there is a caption text that types out "Air Quality Index for " followed by the United States Zip code you entered.

PyPortal Constructor

When we set up the pyportal constructor, we are providing it with these things:

  • url to query
  • json_path to traverse and find the key:value pair we need
  • default_bg default background color
  • details of text and caption fonts, positions, and colors

Fetch

With the PyPortal set up, we can then use pyportal.fetch() to do the query and parsing of the AirNow data and then display it on screen.

Text Position

Depending on the design of your background bitmap and the length of the text you're displaying, you may want to reposition the text and caption. You can do this with the text_position and caption_position options.

The PyPortal's display is 320 pixels wide and 240 pixels high. In order to refer to those positions on the screen, we use an x/y coordinate system, where x is horizontal and y is vertical.

The origin of this coordinate system is the upper left corner. This means that a pixel placed at the upper left corner would be (0,0) and the lower right corner would be (320, 240).

internet_of_things___iot_pyportal_grid.jpg

So, if you wanted to move the subscriber count text to the right and up closer to the top, your code may look like this for that part of the pyportal constructor: text_position=(250, 10)

Text Color

Another way to customize your display is to adjust the color of the text. The line text_color=0xFFFFFF in the constructor shows how. You will need to use the hexadecimal value for any color you want to display.

You can use something like https://htmlcolorcodes.com/ to pick your color and then copy the hex value, in this example it would be 0x0ED9EE

internet_of_things___iot_hecxolor.png

Now, we'll look at mounting the PyPortal into a case for display!

Page last edited March 08, 2024

Text editor powered by tinymce.

PyPortal Air Quality Display Case

wireless_airIMG_4419_2k.jpg

I decided to use the portable PyPortal case designed by the Ruiz Bros. as my enclosure. You can go to this guide to build it -- either by 3D printing it yourself or sending out to a service such as 3DHubs.

weather_IMG_4418_2k.jpg

I didn't need this to be portable, so I omitted the PowerBoost, battery, speaker, and switch.

weather_IMG_4417_2k.jpg

I used all of the same 3D parts, and screwed the mount together, then snapped the top and bottom into place.

weather_IMG_4416_2k.jpg

Magnets

I wanted to mount my PyPortal on my refrigerator, so I affixed magnets.

weather_IMG_4420_2k.jpg
weather_IMG_4420_2k.jpg
weather_IMG_4422_2k.jpg
weather_IMG_4424_2k.jpg

Magnets

 

Use a piece of double stick foam tape to secure the magnetic pin back to the case as shown.

weather_IMG_4426_2k.jpg

I tested it on my workbench drawer and it worked great! Time to place it on the fridge and plug it in!

wireless_airIMG_4431_2k.jpg
wireless_airIMG_4433_2k.jpg

Now, every ten minutes, your display will update with the latest Air Quality Index data. Pay attention if it turns orange or red for the background color -- you may want to change your air filters and be careful outside.

Page last edited March 08, 2024

Text editor powered by tinymce.

Related Guides
Adafruit PyPortal - IoT for CircuitPython
By Kattni Rembor
176
FunHouse IoT Fume Extractor and Air Quality Sensor
By Liz Clark
77
LED Matrix Scoreboard
By Ruiz Brothers
36
Feather RP2350 Audio Reactive Video Synth
By Liz Clark
13
PyPortal Astronauts in Space
By John Park
4
PyPortal IoT Plant Monitor with Google Cloud IoT...
By Brent Rubell
38
Infinite Text Adventure
By Jeff Epler
23
Playing Animated GIF Files in CircuitPython
By Anne Barela
27
QT Py Snap Fit Case
By Ruiz Brothers
37
PyPortal Weekly Countdown Clock
By John Park
4
CircuitPython Day 2020 Countdown Clock
By Anne Barela
9
CircuitPython Elgato WiFi Light Controller
By Liz Clark
12
Adafruit Swirly Aluminum Mounting Grid for 0.1"...
By Kattni Rembor
10
Prop-Maker Feather Talking Adabot Clock
By Liz Clark
15
PyPortal Adafruit Quote Book
By John Park
18
PyPortal Winamp MP3 Player
By Tim C
50
Search

Search

Categories