Weather Station Layout

Run the Weather Station Layout MicroSim Fullscreen
Edit in the p5.js Editor

About This MicroSim

A weather station display shows three kinds of data, and each one changes at a different speed:

Panel	Data source	Typical update
Time	DS3231 real-time clock	Every minute
Indoor temperature and humidity	DHT22 sensor	Every 5 to 10 minutes
Forecast icon, high and low	Open-Meteo over WiFi	Every 1 to 3 hours

The gray square is a mock 152 by 152 pixel e-paper screen. You can drag each panel to move it and drag its corner to resize it. Hover over a panel to see its data source and update interval. The info box also checks whether the time digits are tall enough to read from across a room, and warns you if two panels overlap (then updating one panel forces the other to be redrawn too).

Press Simulate day to run a 24-hour timeline. The MicroSim counts the updates, the partial and full refreshes, and the WiFi connections, then estimates the battery life on a 500 mAh cell.

The energy model is deliberately simple: the Pico sleeps at 0.3 mA between updates, wakes for 0.2 s at 25 mA for each update, a partial refresh costs 10 mA for 0.25 s plus up to 0.5 s more for a larger area, a full refresh (after every 30 partial refreshes) costs 10 mA for 2 s, and each forecast fetch keeps WiFi on for 4 s at 70 mA. Real parts differ, but the comparisons between layouts and schedules are what matter.

How to Use

Drag the panels into a layout you like, and resize them by dragging a corner.
Hover over each panel to read its data source and update interval.
Choose how often each panel updates with the Time every, Indoor every and Forecast every menus.
Press Simulate day and read the counts and the estimated battery life. Press it again to pause, and once more to continue.
Press Reset layout to go back to the starting design.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

<iframe src="https://dmccreary.github.io/clocks-and-watches/sims/weather-station-layout/main.html"
        height="547px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Grade Level

9-12 (Clocks and Watches with AI)

Duration

20 minutes

Prerequisites

E-paper partial and full refresh (Chapter 19)
The non-blocking due() timer pattern (Chapter 6)
WiFi power cost (Chapters 14 and 18)

Learning Objectives

Students will be able to:

Design a readable layout for a small e-paper weather display
Evaluate how each panel's update interval changes refreshes, WiFi connections and battery life
Justify an update schedule by matching it to how fast each kind of data changes

Activities

Baseline (4 min): Without changing anything, press Simulate day. Record the refresh counts, WiFi connections and battery life.
Which schedule matters? (8 min): Change one menu at a time and simulate again: forecast every 30 minutes, then every 6 hours; indoor every 1 minute, then every 30 minutes; time every 5 minutes. Which single change moved the battery life the most? Why does the forecast schedule matter so much more than the indoor schedule?
Design and defend (8 min): Design your own layout for a bedside clock that must be read from the bed. Make the time digits pass the readability check, avoid overlapping panels, and choose a schedule. Simulate a day and write two sentences explaining your trade-offs.

Assessment

The student explains why the forecast panel should update far less often than the time panel.
The student identifies WiFi connections as the most expensive single event in the day.
The student justifies a layout that balances readable digits against refresh cost.

References

Electronic paper - Wikipedia article on bistable e-paper displays and how they refresh.
Open-Meteo API documentation - The free weather forecast service used by the Chrono Smart Clock Kit.
DHT22 / AM2302 sensor - Adafruit guide to the temperature and humidity sensor.
MicroPython framebuf module - The frame buffer used to draw each panel before it is sent to the e-paper display.