Overview
Every summer out in the Atlantic Ocean, storms form off the West coast of Africa and start moving towards North America. Sometimes they dissipate and are gone. Other times they keep growing as they move and can become hurricanes.
This plot of historical storm tracks shows how everything from Panama to Nova Scotia is a potential target.
Hurricanes are very powerful, so when they hit land, it's a serious event. Typical preparation involves boarding up windows, stocking provisions, and getting ready for possible evacuation. So keeping an eye on storm progress is a key part of dealing with hurricane season.
In this guide, we'll show you how you can use your Adafruit PyPortal to display current storm locations. The code is written in CircuitPython.
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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!
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).
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!
You will see a new disk drive appear called PORTALBOOT.
Drag the adafruit-circuitpython-pyportal-<whatever>.uf2 file to PORTALBOOT.
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.
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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.
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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.
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_ssidyour_wifi_password
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_ssidyour_wifi_passwordyour_aio_usernameyour_aio_key
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.
Here is an example settings.toml file.
# 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 (decimal numbers), octal (
0o567) and binary (0b11011) are not supported.
- Floats (decimal numbers), octal (
- Use
\uescapes for weird characters,\xand\oooescapes are not available in .toml files- Example:
\U0001f44dfor 👍 (thumbs up emoji) and\u20acfor € (EUR sign)
- Example:
- Unicode emoji, and non-ASCII characters, stand for themselves as long as you're careful to save in "UTF-8 without BOM" format
When your settings.toml file is ready, you can save it in your text editor with the .toml extension.
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.
import os
print(os.getenv("test_variable"))
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.
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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:
# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
from os import getenv
import adafruit_connection_manager
import adafruit_requests
import board
import busio
from digitalio import DigitalInOut
# Use this import for adafruit_esp32spi version 11.0.0 and up.
# Note that frozen libraries may not be up to date.
# import adafruit_esp32spi
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(f"{byte:02X}" for byte in esp.MAC_address))
for ap in esp.scan_networks():
print(f"\t{ap.ssid:<23} RSSI: {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(f"IP lookup adafruit.com: {esp.pretty_ip(esp.get_host_by_name('adafruit.com'))}")
print(f"Ping google.com: {esp.ping('google.com')} ms")
# 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!")
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.
>>> 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:
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_requestslibrary about them.
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
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.
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.)
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.
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_requestslibrary will parse the JSON into a Python dictionary whose structure is the same as the structure of the JSON.
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.
# 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(f"Fetching JSON data from {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)
Your CIRCUITPY drive should now look similar to the following image:
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.
# SPDX-FileCopyrightText: 2019 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import time
from os import getenv
import board
import busio
import neopixel
import rtc
from digitalio import DigitalInOut
# Use these imports for adafruit_esp32spi version 11.0.0 and up.
# Note that frozen libraries may not be up to date.
# import adafruit_esp32spi
# from adafruit_esp32spi.wifimanager import WiFiManager
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 = "https://time.now/developer/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)
Further Information
For more information on the basics of doing networking in CircuitPython, see this guide:
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Current Storm Information
Getting the information about current storms is super easy. The National Hurricane Center, which is part of NOAA, makes various products available. There's a list here:
At the very end of the "Text Products" list, there is a link to this JSON source:
This has everything we need! You can open the link in a web browser to see the JSON data:
For each storm, there's a name, a location in terms of latitude and logitude, a classification, as well as other ancillary information. And the CircuitPython PyPortal library makes grabbing and parsing this data easy.
This PDF has more information about the JSON data source:
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Hurricane Tracker
OK, let's load up our PyPortal with the hurricane tracker code. You'll need a few additional libraries, as mentioned below. You'll also need the BMP files for the map and icons. And finally, there's the code itself.
Note - the hurricane tracker version provided here is for the Atlantic Ocean only. The NOAA JSON data source also covers the Eastern and Central Pacific. We think adapting this code for those regions would make for a fun knowledge building exercise.
Libraries
In addition to all the libraries needed for the PyPortal (see PyPortal CircuitPython Setup), you'll also need these libraries:
- adafruit_display_shapes
- simpleio
Make sure your CIRCUITPY/lib folder contains them.
This is the sprite sheet bitmap used for the storm icons. Save this as storm_icons.bmp in your CIRCUITPY folder:
# SPDX-FileCopyrightText: 2020 Carter Nelson for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import time
import math
import board
import displayio
import terminalio
from simpleio import map_range
import adafruit_imageload
from adafruit_pyportal import PyPortal
from adafruit_display_text.label import Label
from adafruit_display_shapes.line import Line
# --| User Config |---------------------------------------------------
UPDATE_RATE = 60 # minutes
MAX_STORMS = 3 # limit storms
NAME_COLOR = 0xFFFFFF # label text color
NAME_BG_COLOR = 0x000000 # label background color
ARROW_COLOR = 0x0000FF # movement direction arrow color
ARROW_LENGTH = 15 # movement direction arrow length
LAT_RANGE = (45, 5) # set to match map
LON_RANGE = (-100, -40) # set to match map
# --------------------------------------------------------------------
URL = "https://www.nhc.noaa.gov/CurrentStorms.json"
JSON_PATH = ["activeStorms"]
# setup pyportal
pyportal = PyPortal(
status_neopixel=board.NEOPIXEL,
default_bg="/map.bmp",
)
# setup display group for storms
icons_bmp, icons_pal = adafruit_imageload.load(
"/storm_icons.bmp", bitmap=displayio.Bitmap, palette=displayio.Palette
)
for i, c in enumerate(icons_pal):
if c == 0xFFFF00:
icons_pal.make_transparent(i)
storm_icons = displayio.Group()
pyportal.root_group.append(storm_icons)
STORM_CLASS = ("TD", "TS", "HU")
# setup info label
info_update = Label(
terminalio.FONT,
text="1984-01-01T00:00:00.000Z",
color=NAME_COLOR,
background_color=NAME_BG_COLOR,
)
info_update.anchor_point = (0.0, 1.0)
info_update.anchored_position = (10, board.DISPLAY.height - 10)
pyportal.root_group.append(info_update)
# these are need for lat/lon to screen x/y mapping
VIRTUAL_WIDTH = board.DISPLAY.width * 360 / (LON_RANGE[1] - LON_RANGE[0])
VIRTUAL_HEIGHT = board.DISPLAY.height * 360 / (LAT_RANGE[0] - LAT_RANGE[1])
Y_OFFSET = math.radians(LAT_RANGE[0])
Y_OFFSET = math.tan(math.pi / 4 + Y_OFFSET / 2)
Y_OFFSET = math.log(Y_OFFSET)
Y_OFFSET = (VIRTUAL_WIDTH * Y_OFFSET) / (2 * math.pi)
Y_OFFSET = VIRTUAL_HEIGHT / 2 - Y_OFFSET
def update_display():
# pylint: disable=too-many-locals
# clear out existing icons
while len(storm_icons):
_ = storm_icons.pop()
# get latest storm data
try:
resp = pyportal.network.fetch(URL)
storm_data = pyportal.network.process_json(resp.json(), (JSON_PATH,))[0]
except RuntimeError:
return
print("Number of storms:", len(storm_data))
# parse the storm data
for storm in storm_data:
# don't exceed max
if len(storm_icons) >= MAX_STORMS:
continue
# get lat/lon
lat = storm["latitudeNumeric"]
lon = storm["longitudeNumeric"]
# check if on map
if (
not LAT_RANGE[0] >= lat >= LAT_RANGE[1]
or not LON_RANGE[0] <= lon <= LON_RANGE[1]
):
continue
# OK, let's make a group for all the graphics
storm_gfx = displayio.Group()
# convert to sreen coords
x = int(map_range(lon, LON_RANGE[0], LON_RANGE[1], 0, board.DISPLAY.width - 1))
y = math.radians(lat)
y = math.tan(math.pi / 4 + y / 2)
y = math.log(y)
y = (VIRTUAL_WIDTH * y) / (2 * math.pi)
y = VIRTUAL_HEIGHT / 2 - y
y = int(y - Y_OFFSET)
# icon type
if storm["classification"] in STORM_CLASS:
storm_type = STORM_CLASS.index(storm["classification"])
else:
storm_type = 0
# create storm icon
icon = displayio.TileGrid(
icons_bmp,
pixel_shader=icons_pal,
width=1,
height=1,
tile_width=16,
tile_height=16,
default_tile=storm_type,
x=x - 8,
y=y - 8,
)
# add storm icon
storm_gfx.append(icon)
# add a label
name = Label(
terminalio.FONT,
text=storm["name"],
color=NAME_COLOR,
background_color=NAME_BG_COLOR,
)
name.anchor_point = (0.0, 1.0)
name.anchored_position = (x + 8, y - 8)
storm_gfx.append(name)
# add direction arrow
angle = math.radians(storm["movementDir"])
xd = x + int(ARROW_LENGTH * math.sin(angle))
yd = y - int(ARROW_LENGTH * math.cos(angle))
arrow = Line(x, y, xd, yd, color=ARROW_COLOR)
storm_gfx.append(arrow)
# add the storm graphics
storm_icons.append(storm_gfx)
# update time
info_update.text = storm["lastUpdate"]
# debug
print(
"{} @ {},{}".format(
storm["name"], storm["latitudeNumeric"], storm["longitudeNumeric"]
)
)
# no storms? at least say something
if not len(storm_icons):
print("No storms in map area.")
storm_icons.append(
Label(
terminalio.FONT,
scale=4,
x=50,
y=110,
text="NO STORMS\n IN AREA",
color=NAME_COLOR,
background_color=NAME_BG_COLOR,
)
)
# --------------------------------------------------------------------
# M A I N
# --------------------------------------------------------------------
update_display()
last_update = time.monotonic()
while True:
now = time.monotonic()
if now - last_update > UPDATE_RATE * 60:
print("Updating...")
update_display()
last_update = now
Make sure your PyPortal CIRCUITPY drive has these files in the right directories:
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How It Works
Getting Storm Information
Having a JSON source makes things really easy. And the PyPortal library makes getting that data easy as well. The location is provided when we created the PyPortal object:
# setup pyportal
pyportal = PyPortal(
url="https://www.nhc.noaa.gov/CurrentStorms.json",
json_path=["activeStorms"],
status_neopixel=board.NEOPIXEL,
default_bg="/map.bmp",
)
We give it the URL as well as the path location to where we'll find the data. Note that the background map BMP is also specified.
Then, to actually go fetch the data, we just call fetch():
storm_data = pyportal.fetch()
And if everything works (network connection, etc.), then we should get back a Python list. The list will have a dictionary for each storm. Each dictionary has all the info we want, and we simply access the data via its associated key. For example, the name:
storm["name"]
Computing Screen Coordinates
The storm location in the JSON file is provided in terms of latitude and longitude. So some work must be done to convert that into screen (x, y) coordinates. See this other guide for a more in depth discussion of what is involved:
The same general approach is used for the hurricane tracker.
Storm Icons
The storm icons are contained in a single BMP. This uses the concept of a sprite sheet, which can break down the single BMP into tiles, with each tile containing a single icon. For more information about sprite sheets, see here:
In this case, each icon is 16x16 pixels. There are 3 of them, so the total bitmap size is 16x48 pixels. A background color of yellow is used so that it can easily be found and set as the transparency color. That's what these lines of code do:
for i, c in enumerate(icons_pal):
if c == 0xFFFF00:
icons_pal.make_transparent(i)
Here's a summary of what the icons mean:
Storm Graphics Group
For each storm found, the tracker will display 3 things at the storm location:
- An icon based on storm classification
- The storm name
- An arrow indicating storm movement direction
To make it easy to place all of these items, a new displayio.Group is created for each storm. That's what this line does:
storm_gfx = displayio.Group(max_size=3) # icon + label + arrow
Then each of the items are added via the append() function. And then the group itself is added to the main display ground via this line:
storm_icons.append(storm_gfx)
This is a good example of how nesting groups within groups can be useful.
Putting It All Together
How all this comes together is pretty simple. The initial setup of the PyPortal specifies the JSON data source and background map. That, along with your secrets.py file for connecting to your network, sets up most of the hardware.
Then, the current JSON data is fetched. For each storm found within the map region, it's (x, y) location on the screen is computed and the proper icon and other graphics are shown.
And that's it. With a simple time check, this same process is then repeated at regular intervals.
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