Lab 09: One Clock, Ten Modes

mode-template.py puts ten clock faces in one program. Tap MODE to go to the next one. A row of ten dots along the bottom shows which mode you are in. It starts in the Big Clock.

Welcome to Lab 09

This is the finished clock: weather, an alarm, a timer, a stopwatch, a railway clock, and a holiday calendar, all behind one button. Each mode is its own small file, so you can change one, or add your own. Let's make time tick!

What You Will Learn

• how one program can switch between many faces
• why a small computer loads only one face at a time
• how the alarm and timer can interrupt whatever mode is showing

Run It

Open mode-template.py and click Run. To make it start at power-up instead of the Big Clock:

mpremote cp mode-template.py :main.py

The Ten Modes

Dot	Mode	UP / DOWN	Hold MODE
0	Big Clock	volume	set the clock from the internet
1	Time + temperature	UP: get the weather now	set the clock from the internet
2	Time + temperature + forecast	UP: get the weather now	set the clock from the internet
3	Alarm	UP: alarm on/off, DOWN: hear the tone	set the alarm
4	Timer	UP: start/pause, DOWN: reset	set the time
5	Stopwatch	UP: start/stop, DOWN: lap or reset	set the clock from the internet
6	Analog watch	—	set the clock from the internet
7	Railway clock	—	set the clock from the internet
8	Phrase of the day	other phrases	set the clock from the internet
9	US holiday calendar	next / previous month	set the clock from the internet

1 and 2: Weather

Modes 1 and 2 show the temperature outside, and mode 2 adds the high, low, and weather for today and tomorrow. The forecast comes from Open-Meteo, a free weather service that needs no account. It uses LATITUDE and LONGITUDE from config.py, and fetches new weather every 30 minutes.

3: Alarm

Hold MODE to set the alarm. The part you are setting turns yellow. Use UP and DOWN to change it, and tap MODE for the next part: hour, minute, tone, alarm on or off, and the hourly chime. While you are setting it, MODE belongs to the alarm, so a tap can't switch modes by accident.

When the alarm time comes, the clock switches to this screen from any mode and rings. Any button stops it.

4 and 5: Timer and Stopwatch

The timer counts down and beeps at zero, even if you've switched to another mode. The stopwatch keeps running too: it remembers when it started, so the time is still right when you come back.

6 and 7: Analog and Railway

Mode 6 is the analog watch face from the Chrono Smart Clock Kit. Mode 7 is the Swiss station clock from the Railway Clock Kit, whose red second hand waits at 12 every minute.

8: Phrase of the Day

A new phrase every day, picked by the day of the year, so everyone with this kit sees the same one on the same day. UP and DOWN show other phrases.

Lines of text get shorter toward the bottom of a round screen, so the mode works out how many letters fit on each row and fills the rows one word at a time.

9: Holiday Calendar

Today has a white box. Federal holidays are red, and other holidays are blue. Under the grid are the next three holidays.

Most holidays don't have a fixed date. Thanksgiving is "the fourth Thursday in November." So holidays.py keeps the rules and works out the dates for any year. The calendar never runs out.

Only One Mode at a Time

The Pico W has about 190 KB of memory for Python, and all ten faces together would not fit. So when you tap MODE, the program:

1. asks the current mode to stop(), and keeps what it hands back
2. removes that mode from memory and tidies up the free space
3. loads the next mode fresh and calls its start()

Small computers, small backpacks

Think of the Pico as carrying one textbook at a time. It puts one back on the shelf before taking the next. Things every mode needs, like the alarm time and the volume, stay in shared.py, which never goes back on the shelf.

That's also how the alarm and timer interrupt you. The main program, not any one mode, checks the alarm once a minute. A running timer hands back the moment it will finish when you leave it, and the main program switches back to it right then.

Every Mode Has the Same Functions

mode-template.py only knows four things about a mode:

Function	What it does
start(display, up, down, saved)	Draw the whole screen
update(now)	Called over and over: read UP and DOWN, redraw what changed
on_mode(kind)	Optional: use a MODE press (short or long) for itself
stop()	Turn things off, and hand back anything to remember

So an eleventh mode is just one more file with those functions. The top of mode-template.py explains how to add it.

Try This

1. Set DEMO_SECONDS = 8 in mode-template.py. The clock steps through the modes by itself, like a display in a shop window.
2. Add your own phrase to the list in mode_phrase.py.
3. Make an eleventh mode: copy mode_big.py to mode_mine.py, change its colors, and add ("mode_mine", "Mine") to MODES in mode-template.py. Is there room for eleven dots?

If It Doesn't Work

• No weather. Check that Lab 06 passes, then check LATITUDE and LONGITUDE in config.py. Press UP in mode 1 to try again.
• MemoryError when you change modes. Unplug the Pico and plug it back in, so it starts with fresh memory. If you changed a mode, check that its stop() turns off everything it started.
• The alarm didn't ring. Is it on? Mode 3 shows ALARM ON or ALARM OFF.

Ten Clocks in One!

You've run a program that loads one mode at a time and still keeps the alarm and timer working in the background. You know the four functions every mode needs, so you can build the eleventh.

Back to: Big Round Speaker Clock Kit