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 MagTag_Tides/ 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: 2020 Carter Nelson for Adafruit Industries
#
# SPDX-License-Identifier: MIT
import time
import terminalio
import displayio
import adafruit_imageload
from adafruit_display_text import label
from adafruit_bitmap_font import bitmap_font
from adafruit_magtag.magtag import MagTag
# --| USER CONFIG |--------------------------
STATION_ID = (
"9447130" # tide location, find yours here: https://tidesandcurrents.noaa.gov/
)
METRIC = False # set to True for metric units
VSCALE = 2 # pixels per ft or m
DAILY_UPDATE_HOUR = 3 # 24 hour format
DST_ON = True # Day Light Saving currently active?
# -------------------------------------------
# don't change these
PLOT_WIDTH = 116
PLOT_HEIGHT = 116
PLOT_X = 174
PLOT_Y = 6
PLOT_Y_SCALE = round(PLOT_HEIGHT / (4 * VSCALE))
DATE_FONT = bitmap_font.load_font("/fonts/Kanit-Black-24.bdf")
TIME_FONT = bitmap_font.load_font("/fonts/Kanit-Medium-20.bdf")
# our MagTag
magtag = MagTag()
magtag.json_path = ["predictions"]
# ----------------------------
# Grid overlay for plot
# ----------------------------
grid_bmp, grid_pal = adafruit_imageload.load("/bmps/tides_bg_land.bmp")
grid_pal.make_transparent(1)
grid_overlay = displayio.TileGrid(grid_bmp, pixel_shader=grid_pal)
# ----------------------------
# Tide plot (bitmap, palette, tilegrid)
# ----------------------------
tide_plot = displayio.Bitmap(PLOT_WIDTH, PLOT_HEIGHT, 4)
tide_pal = displayio.Palette(4)
tide_pal[0] = 0x000000 # black
tide_pal[1] = 0x555555 # dark gray
tide_pal[2] = 0xAAAAAA # light gray
tide_pal[3] = 0xFFFFFF # white
tide_pal.make_transparent(3)
tide_tg = displayio.TileGrid(tide_plot, pixel_shader=tide_pal, x=PLOT_X, y=PLOT_Y)
# ----------------------------
# Plot scale labels
# ----------------------------
plot_y_pos = label.Label(terminalio.FONT, text="+99", color=0x000000)
plot_y_pos.text = "{:>3}".format(PLOT_Y_SCALE)
plot_y_pos.anchor_point = (1.0, 0.5)
plot_y_pos.anchored_position = (178, 34)
plot_y_neg = label.Label(terminalio.FONT, text="-99", color=0x000000)
plot_y_neg.text = "{:>3}".format(-1 * PLOT_Y_SCALE)
plot_y_neg.anchor_point = (1.0, 0.5)
plot_y_neg.anchored_position = (178, 92)
plot_y_labels = displayio.Group()
plot_y_labels.append(plot_y_pos)
plot_y_labels.append(plot_y_neg)
# ----------------------------
# Date label
# ----------------------------
date_label = displayio.Group()
date_text = [label.Label(DATE_FONT, text="A", color=0xFFFFFF) for _ in range(5)]
y_offset = 8
for text in date_text:
date_label.append(text)
text.anchor_point = (0.5, 0)
text.anchored_position = (20, y_offset)
y_offset += 23
# ----------------------------
# HiLo Times and Icons
# ----------------------------
tide_info = displayio.Group()
hilo_times = [label.Label(TIME_FONT, text="12:34 P", color=0x000000) for _ in range(4)]
y_offset = 18
for hilo in hilo_times:
tide_info.append(hilo)
hilo.hidden = True
hilo.anchor_point = (1, 0.5)
hilo.anchored_position = (158, y_offset)
y_offset += 28
icon_bmp, icon_pal = adafruit_imageload.load("/bmps/tides_icons.bmp")
icon_pal.make_transparent(1)
hilo_icons = [
displayio.TileGrid(
icon_bmp,
pixel_shader=icon_pal,
width=1,
height=1,
tile_width=24,
tile_height=24,
)
for _ in range(4)
]
y_offset = 6
for icon in hilo_icons:
tide_info.append(icon)
icon.hidden = True
icon.x = 46
icon.y = y_offset
y_offset += 28
# ----------------------------
# Station ID
# ----------------------------
station_info = label.Label(
terminalio.FONT, text="STATION ID: " + STATION_ID, color=0x000000
)
station_info.anchor_point = (1, 1)
station_info.anchored_position = (158, 126)
# ----------------------------
# Add all the graphic layers
# ----------------------------
magtag.splash.append(tide_tg)
magtag.splash.append(grid_overlay)
magtag.splash.append(plot_y_labels)
magtag.splash.append(tide_info)
magtag.splash.append(date_label)
magtag.splash.append(station_info)
# /////////////////////////////////////////////////////////////////////////
def get_data_source_url(station=STATION_ID, metric=METRIC, hilo_only=True):
"""Build and return the URL for the tides API."""
date = "{}{:02}{:02}".format(now.tm_year, now.tm_mon, now.tm_mday)
URL = "https://api.tidesandcurrents.noaa.gov/api/prod/datagetter?format=json"
URL += "&product=predictions"
URL += "&interval=hilo" if hilo_only else ""
URL += "&datum=mllw" # MLLW = "tides"
URL += "&units=metric" if metric else "&units=english"
URL += "&time_zone=lst_ldt" if DST_ON else "&time_zone=lst"
URL += "&begin_date=" + date
URL += "&end_date=" + date
URL += "&station=" + station
return URL
def get_tide_data():
"""Fetch JSON tide data and return parsed results in a list."""
# Get raw JSON data
magtag.url = get_data_source_url(hilo_only=False)
raw_data = magtag.fetch()
# Results will be stored in a list that is PLOT_WIDTH long
new_tide_data = [PLOT_HEIGHT - 1] * PLOT_WIDTH
# Convert raw data to display coordinates
for data in raw_data:
_, t = data["t"].split(" ") # date and time
h, m = t.split(":") # hours and minutes
v = data["v"] # water level
x = round((PLOT_WIDTH - 1) * (60 * float(h) + float(m)) / 1434)
y = (PLOT_HEIGHT // 2) - round(VSCALE * float(v))
y = 0 if y < 0 else y
y = PLOT_HEIGHT - 1 if y >= PLOT_HEIGHT else y
new_tide_data[x] = y
return new_tide_data
def get_hilo_data():
"""Get high / low times."""
# Get raw JSON data
magtag.url = get_data_source_url(hilo_only=True)
return magtag.fetch()
def show_today():
"""Display month and day."""
month_text = (
"JAN",
"FEB",
"MAR",
"APR",
"MAY",
"JUN",
"JUL",
"AUG",
"SEP",
"OCT",
"NOV",
"DEC",
)[now.tm_mon - 1]
day_text = "{:2}".format(now.tm_mday)
date_label[0].text = month_text[0]
date_label[1].text = month_text[1]
date_label[2].text = month_text[2]
date_label[3].text = day_text[0]
date_label[4].text = day_text[1]
def plot_tides():
"""Graphical plot of water level."""
tide_plot.fill(3)
for x in range(PLOT_WIDTH):
y = tide_data[x]
for yfill in range(y, PLOT_HEIGHT):
try:
tide_plot[x, yfill] = 2
except IndexError:
pass
tide_plot[x, y] = 0
def show_hilo():
"""Show high / low times."""
for i in hilo_icons:
i.hidden = True
for t in hilo_times:
t.hidden = True
for i, data in enumerate(hilo_data):
# make it visible
hilo_icons[i].hidden = False
hilo_times[i].hidden = False
# icon
hilo_icons[i][0] = 0 if data["type"] == "H" else 1
# time
h, m = data["t"].split(" ")[1].split(":")
m = int(m)
h = int(h)
ampm = "A" if h < 12 else "P"
h = h if h < 13 else h - 12
hilo_times[i].text = "{:>2}:{:02} {}".format(h, m, ampm)
def time_to_sleep():
"""Compute amount of time to sleep."""
# daily event time
event_time = time.struct_time(
(now[0], now[1], now[2], DAILY_UPDATE_HOUR, 0, 0, -1, -1, now[8])
)
# how long is that from now?
remaining = time.mktime(event_time) - time.mktime(now)
# is that today or tomorrow?
if remaining < 0: # ah its aready happened today...
remaining += 24 * 60 * 60 # wrap around to the next day
# return it
return remaining
# ===========
# M A I N
# ===========
# get current time
magtag.get_local_time()
now = time.localtime()
# show today's date
show_today()
# get and plot tide levels
tide_data = get_tide_data()
plot_tides()
# get and show hilo tide times
hilo_data = get_hilo_data()
show_hilo()
# refresh display
time.sleep(magtag.display.time_to_refresh + 1)
magtag.display.refresh()
time.sleep(magtag.display.time_to_refresh + 1)
# ZZZZZZzzzzzzzzz
now = time.localtime()
magtag.exit_and_deep_sleep(time_to_sleep())
#
# code.py runs again when board wakes up
#
Tide Information Display
Once the code runs, the MagTag display should update to show the information below.
Page last edited January 21, 2025
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