Getting the Program's Files
To use the application, you need to obtain code.py with the program, and the 50_cent.bmp file to place on the MagTag CIRCUITPY drive.
Thankfully, this can be done 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.
Connect your board to your computer via a known good data+power USB cable. The board should show up in your File Explorer/Finder (depending on your operating system) as a flash drive named CIRCUITPY.
Extract the contents of the zip file, copy the lib directory files to CIRCUITPY/lib. Copy the code.py and 50_cent.bmp file to your CIRCUITPY drive. The program should self start.
Drive Structure
After copying the files, your drive should look like the listing below. It can contain other files as well, but must contain these at a minimum.
# SPDX-FileCopyrightText: 2025 Tim C, written for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
50 Cent Consumer Price Index Tracker
This project illustrates how to fetch CPI data from the
US Bureau of Labor Statistics API. CPI data from 1994,
when 50 Cent adopted his moniker, is compared with the latest
data to determine how much 50 Cent from 1994 is worth today.
This project was inspired by: https://50centadjustedforinflation.com/
"""
import json
import os
import time
import alarm
import displayio
from displayio import OnDiskBitmap, TileGrid, Group
import supervisor
from terminalio import FONT
import wifi
import adafruit_connection_manager
from adafruit_display_text.text_box import TextBox
import adafruit_requests
# CPI Data URL
latest_cpi_url = "https://api.bls.gov/publicAPI/v2/timeseries/data/CUUR0000SA0"
# CUUR0000SA0 the series ID for CPI-U (All items)
# Note: bls.gov API is limited to 20 requests per day for unregistered users
# CPI value for June 1994
june_94_cpi = 148.0
# Get WiFi details, ensure these are setup in settings.toml
ssid = os.getenv("CIRCUITPY_WIFI_SSID")
password = os.getenv("CIRCUITPY_WIFI_PASSWORD")
# Initalize Wifi, Socket Pool, Request Session
pool = adafruit_connection_manager.get_radio_socketpool(wifi.radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(wifi.radio)
requests = adafruit_requests.Session(pool, ssl_context)
try:
# Connect to the WiFi network
wifi.radio.connect(ssid, password)
except OSError as ose:
print(f"OSError: {ose}")
print("Wifi connected!")
# Get display reference
display = supervisor.runtime.display
# Set to portrait orientation
display.rotation = 0
# Group to hold all visual elements
main_group = Group()
# Full display sized white background
white_bg_group = Group(scale=8)
white_bg_bmp = displayio.Bitmap(display.width // 8, display.height // 8, 1)
white_bg_palette = displayio.Palette(1)
white_bg_palette[0] = 0xFFFFFF
white_bg_tg = TileGrid(bitmap=white_bg_bmp, pixel_shader=white_bg_palette)
white_bg_group.append(white_bg_tg)
main_group.append(white_bg_group)
# 50 Cent photo
photo_bmp = OnDiskBitmap("50_cent.bmp")
photo_tg = TileGrid(bitmap=photo_bmp, pixel_shader=photo_bmp.pixel_shader)
main_group.append(photo_tg)
def get_latest_cpi_value():
"""
Fetch the latest CPI data from BLS API.
:return: tuple containing (latest CPI value, month, year)
"""
try:
response = requests.get(latest_cpi_url)
try:
json_data = response.json()
except json.decoder.JSONDecodeError as json_error:
raise Exception(f"JSON Parse error: {response.text}") from json_error
latest_data = json_data["Results"]["series"][0]["data"][0]
return (
float(latest_data["value"]),
latest_data["periodName"],
latest_data["year"],
)
except Exception as e:
raise Exception(f"Error fetching data from BLS API: {e}") from e
# fetch the latest CPI data
latest_cpi_value, month, year = get_latest_cpi_value()
# Label for the message below the photo
message_lbl = TextBox(
FONT,
128,
TextBox.DYNAMIC_HEIGHT,
align=TextBox.ALIGN_CENTER,
text=f"As of {month} {year}\n50 Cent is worth",
color=0x000000,
scale=1,
)
message_lbl.anchor_point = (0, 0)
message_lbl.anchored_position = (0, photo_tg.tile_height + 6)
main_group.append(message_lbl)
# calculate current value of 50 cents from 1994
current_value = round(50.0 * (latest_cpi_value / june_94_cpi) + 0.5)
# Label for the calculated value
amount_lbl = TextBox(
FONT,
128 // 3,
TextBox.DYNAMIC_HEIGHT,
align=TextBox.ALIGN_CENTER,
text=f"{current_value}",
color=0x000000,
scale=3,
)
amount_lbl.anchor_point = (0, 0)
amount_lbl.anchored_position = (0, photo_tg.tile_height + message_lbl.height + 12)
main_group.append(amount_lbl)
# Cent label at bottom of display
cent_lbl = TextBox(
FONT,
128,
TextBox.DYNAMIC_HEIGHT,
align=TextBox.ALIGN_CENTER,
text="Cent",
color=0x000000,
scale=1,
)
cent_lbl.anchor_point = (0, 1)
cent_lbl.anchored_position = (0, display.height - 2)
main_group.append(cent_lbl)
# set main_group showing on the display
display.root_group = main_group
display.refresh()
# Sleep for 1 day
al = alarm.time.TimeAlarm(monotonic_time=time.monotonic() + 86400)
alarm.exit_and_deep_sleep_until_alarms(al)
# Does not return. Exits, and restarts after 1 day
Page last edited November 14, 2025
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