Hannah's Sensor Watch Face Reference Manual

REPETITION MINUTE face

A hopefully useful complication for friendly neighbors in the dark

Originating from 1676 from reverend and mechanician Edward Barlow, and perfected in 1820 by neighbor Abraham Breguet, a minute repeater or "repetition minute" is a complication in a mechanical watch or clock that chimes the hours and often minutes at the press of a button. There are many types of repeater, from the simple repeater which merely strikes the number of hours, to the minute repeater which chimes the time down to the minute, using separate tones for hours, quarter hours, and minutes. They originated before widespread artificial illumination, to allow the time to be determined in the dark, and were also used by the visually impaired.

How to use it :

Long press the light button to get an auditive reading of the time like so :
0..23 (1..12 if 24-hours format isn't enabled) low beep(s) for the hours
0..3 low-high couple pitched beeps for the quarters
0..14 high pitched beep(s) for the remaining minutes

Prerequisite : a watch with a working buzzer

~ Only in the darkness can you see the stars. - Martin Luther King ~

ALARM face

Implements up to 16 alarm slots on the sensor watch

Usage:
- In normal mode, the alarm button cycles through all 16 alarms.
- Pressing the alarm button long in normal mode toggles the corresponding alarm on or off.
(Whereas pressing the alarm button extra long brings you back to alarm no. 1.)
- Pressing the light button enters setting mode and cycles through the settings of each alarm.
(Long pressing the light button enters setting mode without illuminating the led.)
- In setting mode an alarm slot is selected by pressing the alarm button when the slot number
in the upper right corner is blinking.
- For each alarm slot, you can select the day. These are the day modes:
- ED = the alarm rings every day
- 1t = the alarm fires only one time and is erased afterwards
- MF = the alarm fires Mondays to Fridays
- WN = the alarm fires on weekends (Sa/Su)
- MO to SU = the alarm fires only on the given day of week
- You can fast cycle through hour or minute setting via long press of the alarm button.
- You can select the tone in which the alarm is played. (Three pitch levels available.)
- You can select how many "beep rounds" are played for each alarm. 1 to 9 rounds, plus extra
long ('L') and extra short ('o') alarms.
- The simple watch face indicates if any alarm is set within the next 24h by showing the signal indicator.

TIMER face Advanced timer/countdown face with pre-set timer lengths

This watch face provides the functionality of starting a countdown by choosing one out of nine programmable timer presets. A timer/countdown can be 23 hours, 59 minutes, and 59 seconds max. A timer can also be set to auto-repeat, which is indicated by the lap indicator.

How to use in NORMAL mode:
- Short-pressing the alarm button cycles through all pre-set timer lengths. Find the current timer slot number in the upper right-hand corner.
- Long-pressing the alarm button starts the timer.
- Long-pressing the light button initiates settings mode.

How to use in SETTINGS mode:
- There are up to nine slots for storing a timer setting. The current slot is indicated by the number in the upper right-hand corner.
- Short-pressing the light button cycles through the settings values of each timer slot in the following order: hours - minutes - seconds - timer repeat
- Short-pressing the alarm button alters the current settings value.
- Long-pressing the light button resumes to normal mode.

STOCK STOPWATCH face

The Stock Stopwatch face implements the original F-91W stopwatch functionality, including counting hundredths of seconds and lap timing.

Use the ALARM button to start and stop the stopwatch.
Press the LIGHT button while the stopwatch is running to view the lap time.
(The stopwatch continues running in the background, indicated by a blinking colon.)
Press the LIGHT button again to switch back to the running stopwatch.
Press the LIGHT button when the timekeeping is stopped to reset the stopwatch.

There are two improvements compared to the original F-91W:
o When the stopwatch reaches 59:59, the counter does not simply jump back to zero but keeps track of hours in the upper right-hand corner (up to 24 hours).
o Long-press the light button to toggle the LED behavior. It either turns on with each button press or remains off.

NOTE:
This watch face relies heavily on static vars in stock_stopwatch.c. The disadvantage is that you cannot use more than one instance of this watch face on your custom firmware - but then again, who would want that? The advantage is that accessing vars is more direct and faster, and we can save some precious cpu cycles. :-)

Day/night percentage face

Shows the percentage of the way through the day/night the current time is.

The time digits show the percentage of the way through the day/night it is, with decimals in the smaller seconds digits. If the day or night will last for a full 24 hours, the text "Etrnal" is displayed instead of a percentage. The "PM" indicator is set when it is currently nighttime. The weekday and day digits display the weekday and day, as one would expect.

This face does not currently offer any configuration. You must set the location register with some other face.

SUNRISE & SUNSET FACE

The Sunrise/Sunset face is designed to display the next sunrise or sunset for a given location. It also functions as an interface for setting the location register, which other watch faces can use for various purposes.

Refer to the wiki for usage instructions

TOMATO TIMER face

Add a "tomato" timer watch face that alternates between 25 and 5 minute timers as in the Pomodoro Technique.
https://en.wikipedia.org/wiki/Pomodoro_Technique

The top right letter shows mode (f for focus or b for break).
The bottom right shows how many focus sessions you've completed.
(You can reset the count with a long press of alarm)

When you show up and it says 25 minutes, you can start it (alarm), switch to 5 minute (light) mode or leave (mode).

When it's running you can reset (alarm), or leave (mode).

When it's done, we beep and go back to step 1, changing switching mode from focus to break (or break to focus)

MINIMAL CLOCK FACE

A minimal clock face that just shows hours and minutes.
There is nothing to configure. The face follows the 12h/24h setting

Slowly render the current time from left to right, scanning across its liquid crystal face, completing 1 cycle every 2 seconds.

Created to mimic the wyoscan watch that was produced by Halmos and designed by Dexter Sinister
It looks like this https://www.o-r-g.com/apps/wyoscan

You’ll notice that reading this watch requires more attention than usual, as the seven segments of each digit are lit one by one across its display.
This speed may be adjusted until it reaches the limits of your perception. You and your watch are now in tune.

This is a relatively generic way of animating a time display.
If you want to modify the animation, you can change the segment_map the A-F are corresponding to the segments on the watch face
A
F B
G
E C
D
the X's are the frames that will be skipped in the animation
This particular segment_map allocates 8 frames to display each number this is to achieve the 2 second cycle time. 8 frames per number * 6 numbers + the trailing 16 frames = 64 frames at 32 frames per second, this is a 2 second cycle time.

I tried to make the animation of each number display similar to if you were to draw the number on the watch face with a pen, pausing with 'X' when your pen might turn a corner or when you might cross over a line you've already drawn. It is vaguely top to bottom and counter, clockwise when possible.

CLOSE ENOUGH CLOCK FACE

Displays the current time; but only in periods of 5.
Just in the in the formats of:
- "10 past 5"
- "15 to 7"
- "6 o'clock"

ENDLESS_RUNNER face

This is a basic endless-runner, like the Chrome Dino game https://en.wikipedia.org/wiki/Dinosaur_Game.
On the title screen, you can select a difficulty by long-pressing LIGHT or toggle sound by long-pressing ALARM.
LED or ALARM are used to jump.
High-score is displayed on the top-right on the title screen. During a game, the current score is displayed.

BUTTERFLY

A GAME OF SHAPE RECOGNITION AND QUICK REFLEXES FOR 2 PLAYERS

Setup
=====

The game is played by 2 players, each using a distinct button:
- player 1 plays with the LIGHT (upper left) button
- player 2 plays with the ALARM (lower right) button

To play, both players need a firm grip on the watch. A suggested method is to face each other, remove the watch from the wrist, and position it sideways between you. Hold one side of the strap in your preferred hand (right or left) and use your thumb to play.

Start of the game
=================

After the splash screen (BtrFly) is shown, the game proceeds through a couple configuration screens. Use ALARM to cycle through the possible values, and LIGHT to validate and move to the next screen.

The configuration options are:

- snd y/n Toggle sound effects on or off
- goal 3/6/9 Choose to play a game of 3, 6 or 9 points
- cont y/n Decide to continue an unfinished game or start a new one (this option appears only if a game is in progress)

Rules
=====

Prior to each round, a symmetrical shape composed of 2 characters is shown in the center of the screen. This shape, representing a butterfly's wings, is randomly chosen from a set of a dozen or so possible shapes. For example:

][

Memorize this shape! Your objective in the round will be to "catch" this "butterfly" by pressing your button before your opponent does.

Once you believe you've memorized the shape, press your button. The round officially begins as soon as either player presses their button.

Various "butterflies" will then appear on the screen, one after the other.
The fastest player to press their button when the correct butterfly is shown wins the round. However, if a player presses their button when an incorrect butterfly is shown, they immediately lose the round.

Scoring
=======

The scores are displayed at the top of the screen at all times.

When a round is won by a player, their score increases by one. When a round is lost by a player, their score decreases by one; unless they have a score of 0, in which case it remains unchanged.

The game ends when a player reaches the set point goal (3, 6 or 9 points).

simon_face
-----------
The classic electronic game, Simon, reduced to be played on a Sensor-Watch

How to play:

When first arriving at the face, it will show your best score.

Press the light button to start the game.

A sequence will be played, starting with length 1. The sequence can be made up of tones corresponding to any of the three buttons.

light button: "LI" will display at the top of the screen, the LED will be yellow, and a high D will play
mode button: "DE" will display at the left of the screen, the LED will be red, and a high E will play
alarm button: "AL" will display on the right of the screen, the LED will be green, and a high C will play

Once the sequence has finished, press the same buttons to recreate the sequence.

If correct, the sequence will get one tone longer and play again. See how long of a sequence you can get.

If you recreate the sequence incorrectly, a low note will play with "OH NOOOOO" displayed and the game is over.
Press light to play again.

Once playing, long press the mode button when it is your turn to exit the game early.

MOON PHASE face

The Moon Phase face is similar to the Sunrise/Sunset face: it displays the current phase of the moon, along with the day of the month and a graphical representation of the moon on the top row.

This graphical representation is a bit abstract. The segments that turn on represent the shape of the moon, waxing from the bottom right and waning at the top left. A small crescent at the bottom right will grow into a larger crescent, then add lines in the center for a quarter and half moon. All segments are on during a full moon. Then gradually the segments at the bottom right will turn off, until all that remains is a small waning crescent at the top left.

All segments turn off during a new moon.

On this screen you may press the Alarm button repeatedly to move forward in time: the day of the month at the top right will advance by one day for each button press, and both the text and the graphical representation will display the moon phase for that day. Try pressing the Alarm button 27 times now, just to visualize what the moon will look like over the next month.

BOXED BREATHING face

Breathing is a complication for guiding boxed breathing sessions.
Boxed breathing is a technique to help you stay calm and improve concentration in stressful situations.

Usage: Timed messages will cycle as long as this face is active.
Press ALARM to toggle sound.

BEER_O_CLOCK daily alarm face

Basic daily beer alarm clock face.

Also experiments with caret-free UI: One button cycles hours, the other minutes, so there’s no toggling between display and adjust modes and no cycling the caret through the UI.
º LIGHT advances hour by 1
º LIGHT long press advances hour by 6
º ALARM advances minute by 10
º ALARM long press cycles through signal modes (just one at the moment)

Kitchen Conversions
A face that allows the user to convert between common kitchen units of measurement

How to use
----------
Short press the alarm button to move forward through menus, and long press to move backwards

Press the light button to cycle through options in the menus

When inputting a number, the light button moves forward one place and the alarm button increments a digit by one

To convert between Imperial (GB) and US (A) measurements of volume, hold the light button

COUNTDOWN TIMER face

Slight extension of the original countdown face by Wesley Ellis.
- Press the light button to enter setting mode and adjust the countdown timer.
- Start and pause the countdown using the alarm button, similar to the stopwatch face.
- When paused or terminated, press the light button to restore the last entered countdown.

Max countdown is 23 hours, 59 minutes and 59 seconds.

Note: we have to prevent the watch from going to deep sleep using movement_schedule_background_task() while the timer is running.

TIME LEFT face

The Time Left Face helps you to visualize how far you have proceeded in a certain time span. Much like the Day One Face, you can set your beginning date. In addition to that, you also set your target or destination date. You can then use the face to display your progress in different ways.

Usage:

- Long pressing of the light button starts the settings mode:
- First, you set the beginning date (indicated by a 'b' in the upper right corner).
- Start by setting the year (indicated by the letter 'YR'). Use the alarm button to cycle the value. Short pressing the light button brings you to the next settings page.
- Set the values in this order:
a. beginning date (indicated by a 'b'): year - month - day
b. destination date (indicated by a 'd'): year - month - day
- After cycling through all settings pages, the face resumes to display mode.

- In display mode, use the alarm button (short press) to cycle through these four types of display:
a. number of days left ('DL') until the destination date is reached.
b. remaining days expressed as percentage of total time span. The value is shown with two decimals, using the colon as decimal point.
c. number of days passed ('DA') since the beginning date.
d. number of days passed expressed as percentage of total time span. (Two decimal points.)

What is this for?

You can use this watch face to be reminded of any kind of progess between a set start and end date. The brave among us can use it as a kind of memento mori visualization. Set your date of birth and look up the average life expectancy of your age cohort based on publicly available mortality tables. Then, set the statistically expected day of death as the target date and you will be able to see how much of your time has passed and how much is still to come.

Deadline Face

This is a watch face for tracking deadlines. It draws inspiration from other watch faces of the project but focuses on keeping track of deadlines. You can enter and monitor up to four different deadlines by providing their respective date and time. The face has two modes: *running mode* and *settings mode*.

## Running Mode

When the watch face is activated, it defaults to running mode. The top right corner shows the current deadline number, and the main display presents the time left until the deadline. The format of the display varies depending on the remaining time.

- When less than a day is left, the display shows the remaining hours, minutes, and seconds in the form `HH:MM:SS`.

- When less than a month is left, the display shows the remaining days and hours in the form `DD:HH` with the unit `dy` for days.

- When less than a year is left, the display shows the remaining months and days in the form `MM:DD` with the unit `mo` for months.

- When more than a year is left, the years and months are displayed in the form `YY:MM` with the unit `yr` for years.

- When a deadline has passed in the last 24 hours, the display shows `over` to indicate that the deadline has just recently been reached.

- When no deadline is set for a particular slot, or if a deadline has already passed by more than 24 hours, `--:--` is displayed.

The user can navigate in running mode using the following buttons:

- The *alarm button* moves the next deadline. There are currently four slots available for deadlines. When the last slot has been reached, pressing the button moves to the first slot.

- A *long press* on the *alarm button* activates settings mode and enables configuring the currently selected deadline.

- A *long press* on the *light button* activates a deadline alarm. The bell icon is displayed, and the alarm will ring upon reaching any of the deadlines set. It is important to note that the watch will not enter low-energy sleep mode while the alarm is enabled.

## Settings Mode

In settings mode, the currently selected slot for a deadline can be configured by providing the date and the time. Like running mode, the top right corner of the display indicates the current deadline number. The main display shows the date and, on the next page, the time to be configured.

The user can use the following buttons in settings mode.

- The *light button* navigates through the different date and time settings, going from year, month, day, hour, to minute. The selected position is blinking.

- A *long press* on the light button resets the date and time to the next day at midnight. This is the default deadline.

- The *alarm button* increments the currently selected position. A *long press* on the *alarm button* changes the value faster.

- The *mode button* exists setting mode and returns to *running mode*. Here the selected deadline slot can be changed.

PROBABILITY face

This face is a dice-rolling random number generator.
Supports dice with 2, 4, 6, 8, 10, 12, 20, or 100 sides.

Press LIGHT to cycle through die type.
The current die size is indicated on the left ("C" for 100)

Press ALARM to roll the selected die.

A extremely simple coin flip face.

Press ALARM or LIGHT to flip a coin, after a short animation it will display "Heads" or "Tails". Long-press to flip again (you can change a #define to allow a short-press to reflip as well, if you'd like).

This is for people who want a simpler UI than probability_face or randonaut_face. While those have more features, this one is more immediately obvious - useful, for instance, if you are using a coin flip to agree on something with someone, and want the operation to be clear to someone who has not had anything explained to them.

GEOMANCY watch face

A simple and straightforward watch face for the ancient Eastern geomantic divination system of I Ching and the western system of "Geomancy". It is an optional addition to the Toss Up Face.

The LIGHT button toggles between the two systems of geomancy.

The ALARM button casts an I Ching hexagram or Geomantic figure based on drawing virtual stalks from the True Random Number Generator in the Sensor Watch.

The figures are flipped 90 degrees clockwise, so the left side is the bottom and the right side the top.

LONG PRESSING ALARM toggles the display of the King Wen sequence index for the cast I Ching Hexagram (https://en.wikipedia.org/wiki/King_Wen_sequence) or the abbreviated name for the cast Geomantic Figure:

GF - Greater Fortune (Fortuna Major)
LF - Lesser Fortune (Fortuna Minor)
PO - Populus
VI - Via
AL - Albus
CO - Conjunctio
PA - Puella
AM - Amissio
PR - Puer
RU - Rubeus
AQ - Acquisitio
LA - Laetitia
TR - Tristitia
CA - Carcer
HD - Head of the Dragon (Caput Draconis)
TD - Tail of the Dragon (Cauda Draconis)

RATE METER face

The rate meter shows the rate per minute at which the ALARM button is being pressed. This is particularly useful in sports where cadence tracking is useful. For instance, rowing coaches often use a dedicated rate meter - clicking the rate button each time the crew puts their oars in the water to see the rate (strokes per minute) on the rate meter.

BLINKY LIGHT face

The blinky light watch face was designed as a tutorial for making a watch face in Movement, but it actually might be useful to have a blinking light in a pinch.

The screen displays the name of the watch face (”BL”), as well as an S at the top right for slow blink or an F for fast blink. The bottom line selects the color: green, red or yellow. You can change the speed of the blinking light by pressing the Alarm button, and change the color with the Light button. A long press on the Alarm button starts the blinking light, and another long press stops it.

Note that this will chew through your battery! The green LED uses about 450µA at full brightness, which is 45 times the normal power consumption of the watch. The red LED is an order of magnitude less efficient (4500 µA), and the yellow setting lights both LEDs, which chews through nearly 5 milliamperes. This means that one hour of yellow blinking is likely to eat up between 2 and 3 percent of the battery’s usable life!

Still, if you need to signal your location to someone in a dark forest, this watch face could come in handy. Just try to use the green LED as much as you can.

Simple Calculator

How to use:

Flow:
Enter first number -> Select operator -> Enter second number -> View Results

How to read the display:
- "CA" is displayed at the top to tell you that you're in the CAlculator
- The top-right digit (1, 2, or 3) lets you know whether you're entering the first number (1), entering the second number (2), or viewing the results (3).
- To the right of the top-right digit will show the number's sign. If the number is negative, a "-" will be displayed, otherwise it is empty.
- The 4 large digits to the left are whole numbers and the 2 smaller digits on the right are the tenths and hundredths decimal places.

Entering the first number:
- Press ALARM to increment the selected (blinking) digit
- Press LIGHT to move to the next placeholder
- LONG PRESS the LIGHT button to toggle the number's sign to make it negative
- LONG PRESS the ALARM button to reset the number to 0
- Press MODE to proceed to selecting the operator

Selecting the operator:
- Press the LIGHT button to cycle through available operators. They are:
+ Add
- Subtract
* Multiply
/ Divide
sqrtf() Square root
powf() Power (exponent calculation)
- Press MODE or ALARM to proceed to entering the second number

Entering the second number:
- Everything is the same as setting the first number except that pressing MODE here will proceed to viewing the results

Viewing the results:
- Pressing MODE will start a new calculation with the result as the first number. (LONG PRESS ALARM to reset the value to 0)

Errors: - An error will be triggered if the result is not able to be displayed, that is, if the value is greater than 9,999.99 or less than -9,999.99.
- An error will also be triggered if an impossible operation is selected, for instance trying to divide by 0 or get the square root of a negative number.
- Exit error mode and start over with any button press.

A Metronome watch complication

Allows the user to set the BPM, counts per measure, beep sound on/off

Screen flashes on on the beat and off on the half beat (1/8th note)

Beep will sound high for downbeat and low for subsequent beats in measure

USE:
Press Alarm to start/stop metronome_face
Hold Alarm to enter settings menu
Short Light press will move through options
Short Alarm press will increment/toggle options
Long alarm press will exit options

COUNTER face

Counter face is designed to count the number of running laps during exercises.

Usage:
Short-press ALARM to increment the counter (loops at 99)
Long-press ALARM to reset the counter.
Long-press LIGHT to toggle sound.

Periodic Table Face

Allows for viewing data of the Periodic Table on your wrist.
When looking at an element, it'll show you the atomic number on the center of the screen, symbol on the right, and it's group on the top-right.
Pressing the mode button will cycle through the pages.
Page 1: Atomic Mass
Page 2: Year Discovered
Page 3: Electronegativity
Page 4: Full Name of the Element

Controls:
Mode Press
On Title: Next Screen
Else: Cycle through info of an element
Mode Hold
On Title: First Screen
On Element Symbol Screen: Go to Title Screen
Else: Go to Symbol Screen of current element
If you are in a subscreen and just keep holding MODE, you will go through all of these menus without needing to depress.

Light Press
On Title or Element Symbol Screen: Previous Element
Else: Display currenlt-selected element symbol page Light Hold
On Title Screen or Element Symbol: Fast Cycle through Previous Elements
Else: Activate LED backlight

Alarm Press
On Title or Element Symbol Screen: Next Element
Else: Display currenlt-selected element symbol page Alarm Hold
On Title Screen or Element Symbol: Fast Cycle through Next Elements

VOLTAGE face

This watch face is very simple and has no controls to speak of. It displays the battery voltage as measured by the SAM L22’s ADC.

Note that the Simple Clock watch face includes a low battery warning, so you don’t technically need to this watch face unless you want to track the battery level.

NANOSEC face

The goal of nanosec face is dramatic improvement of SensorWatch accuracy.

Minimum goal is <60 seconds of error per year. Full success is if we can reach <15 seconds per year (<0.47ppm error).

Best used in conjunction with the FINETUNE face.

It implements temperature correction using tempco from datasheet (and allows to adjust these) and allows to introduce offset fix. Therefore requires temperature sensor board.

Most users will need to apply profile 3 ("default") or 2 ("conservative datasheet"), and tune first parameter "static offset" (as it's different for every crystal sample).

Frequency correction is dithered over 31 correction intervals (31x10 minutes or ~5 hours), to allow <0.1ppm correction resolution.
* 1ppm is 0.0864 sec per day.
* 0.1ppm is 0.00864 sec per day.

To stay under 1ppm error you would need calibration of your specific instance of quartz crystal after some "burn-in" (ideally 1 year).

Should improve TOTP experience.

Default funing fork tempco: -0.034 ppm/°C², centered around 25°C
We add optional cubic coefficient, which was measured in practice on my sample

Cadence (CD) - how many minutes between corrections. Default 10 minutes.
Every minute might be too much. Every hour - slightly less power consumption but also less precision.

Can compensate crystal aging (ppm/year) - but you really should be worrying about it on second/third years of watch calibration.

For full usage instructions, please refer to the wiki:
https://www.sensorwatch.net/docs/watchfaces/nanosec/

FINETUNE face

FineTune face allows to align watch with sub-second precision in 25/250ms accuracy. Counts time since previous finetune, and allows to calculate & apply ppm correction for nanosec.

Best used in conjunction with the NANOSEC face.

Main screen - adjust delay (light/alarm)
Long MODE press - show hours since previous finetune
Long MODE press - show calculated ppm correction.
You can apply it with long LIGHT, or just reset finetune timer with long ALARM.

Finetune will apply crystal aging correction on every finetune save (as aging is calculated since "last finetune" timestamp); but you should worry about aging only on second/third years of watch calibration (if you are really looking at less than 10 seconds per year of error).

Warning, do not use at the first second of a month, as you might stay at the same month and it will surprise you. Just wait 1 second...We are not fully replicating RTC timer behavior when RTC is off. Simulating months and years is... too much complexity.

For full usage instructions, please refer to the wiki:
https://www.sensorwatch.net/docs/watchfaces/nanosec/

SET TIME HACKWATCH

This is an extended version of set_time face which allow setting seconds precisely. To achieve that - press and hold alarm button few seconds before 00 and release exaclty as reference clock turns 00.

All settings can go up, or down (long alarm press).

The challenge is that SensorWatch display is delayed 0.5 seconds vs hardware RTC clock. It is caused by interrupts being generated by raising edge of counter. It means there is no way to precisely trigger at 0.5s, as events at different frequencies slightly mismatch. This watch face achieves this approximately by triggering at 15th out of 32Hz events.

If you are <30 seconds when setting seconds - you will stay in the same minute. Otherwise - you will go to next minute.

Note that changing anything will slightly delay subseconds counter. This is why this face sets seconds last to achiveve best precision. Still, best possible precision is achieved with finetune face.

PREFERENCES face

The Preferences watch face allows you to configure various options on your Sensor Watch. Like all other screens, you advance the field you’re setting with the Light button, and advance its value with the Alarm button. The Preferences watch face labels each setting with a two-letter code on the top row; the following list describes each setting and their options:

CL - Clock mode.
This setting allows you to select a 12-or 24-hour clock display. All watch faces that support displaying the time will respect this setting for example, both Simple Clock, World Clock and Sunrise/Sunset will display the time in 24 hour format if the 24 hour clock is selected he

BT - Button tone.
This setting is only relevant if you installed the buzzer connector, and it toggles the beep when changing modes. If Y, the buzzer will sound a tone when Mode is pressed. Change to N to make the Mode button silent.

TO - Timeout.
Sets the time until screens that time out (like Settings and Time Set) snap back to the first screen. 60 seconds is a good default for the stock firmware, but if you choose a custom firmware with faces that you’d like to keep on screen for longer, you can set that here.

LE - Low Energy mode.
Sets the time until the watch enters its low energy sleep mode. Options range from 1 hour to 7 days, or Never. The more often Sensor Watch goes to sleep, the longer its battery will last — but you will lose the seconds indicator while it is asleep. This setting allows you to make a tradeoff between the device’s responsiveness and its longevity.

LT - Light.
This setting has three screens.
The first lets you choose how long the LED should stay lit when the LIGHT button is pressed. Options are 1 second, 3 seconds and 5 seconds, or “No LED” to disable the LED entirely.
The second screen, titled “blu” or “grn”, sets the intensity of the blue or green LED depending on the target Sensor Board hardware. Values range from 0 (off) to 15 (full intensity).
The third screen, “red”, sets the intensity of the red LED, again from 0 to 15.
On the last two screens, the LED remains on so that you can see the effect of mixing the two LED colors. On the Special Edition boards, you’ll have red, blue and a variety of shades of pink and purple to experiment with!

THERMISTOR READOUT (aka Temperature Display)

This watch face is designed to work with either the Temperature + GPIO sensor board or the Temperature + Light sensor board. It reads the current temperature from the thermistor voltage divider on the sensor board, and displays the current temperature in degrees Celsius.

When the watch is on your wrist, your body heat interferes with an ambient temperature reading, but if you set it on a bedside table, strap it to your bike handlebars or place it outside of your tent while camping, this watch face can act as a digital thermometer for displaying ambient conditions.

The temperature sensor watch face automatically samples the temperature once every five seconds, and it illuminates the Signal indicator just before taking a reading.

Pressing the ALARM button toggles the unit display from Celsius to Fahrenheit. Technically this sets the global “Metric / Imperial” flag, so any other watch face that displays localizable units will display them in the system selected here.