Twenty-five faces, a calculator and a converter. Here is how the less obvious parts work.
Swipe the display left or right to cycle the twenty-five faces. Choose which ones are in the rotation from the iPhone app's Faces tab — disabled faces are skipped. On the Classic face, long-press (or press MODE) to cycle Time → Stopwatch → Timer → Dual Time, and turn the Digital Crown to rotate sub-modes both ways.
Just start typing on the numpad — the clock turns into a calculator. C on 0 (or ten idle seconds) returns to the clock. The 2nd key reveals %, √, ± and the memory keys. Turn the Crown to scroll your calculation history and tap a result to recall it.
The same 2nd layer opens three more modes (all LCD-84 Pro): SCI, a full scientific pad — sin/cos/tan and their inverses, ln/log, x², xʸ, 1/x, π and a DRG key for DEG/RAD; from SCI, DATE — days between two dates, or a date plus or minus N days, with a TODAY key; and TIME — h:mm duration math with carry. C always exits straight back to the plain calculator, from any of the three.
On the Calculator face, type a number, press 2nd then CONV. A list opens — turn the Digital Crown to scroll it, tap to pick. Every conversion is listed in both directions (AUD→USD and USD→AUD are separate rows), so there is no direction key to remember. While you are converting, the 2nd key becomes CUR, so reopening the list is a single tap.
Your home currency converts against six counters — the US dollar, euro, yen, pound, Australian dollar and New Zealand dollar. Rates come from the European Central Bank once a day and are cached on the watch, so conversions keep working with no signal — they just stop refreshing.
Set your home currency in the iPhone app under Customize → Converter. Units — km/miles, cm/inches, kg/lb, °C/°F, litres/gallons — are always available and need no network at all.
The converter is part of LCD-84 Pro. Without the unlock, CONV shows a PRO badge instead of opening.
Swipe to the UFO Game face — it opens as a watch. Tap to start, steer the ship with the Digital Crown, tap to fire (every shot beeps, hit or miss). Three landed UFOs end the game; long-press returns to Time mode. Car Race and Number Invaders work the same way — a watch until you tap, then a game.
watchOS returns to its own face after a delay. On the watch: Settings → General → Return to Clock, scroll to the app list, choose LCD-84 → Return to App / After 1 Hour.
The weather block needs location access: on the watch, Settings → Privacy & Security → Location Services → LCD-84 → While Using. A first fetch can take a few minutes; the app retries automatically.
NO ACCESS means the calendar permission was declined or never answered. Calendar access is granted per device, so the watch asks separately from the iPhone: on the watch, Settings → Privacy & Security → Calendars → LCD-84. Note that iOS 17 removed read-only calendar access, so the system asks for full access — LCD-84 only ever reads, and never creates, edits or deletes anything.
NO EVENTS means access is working and there is genuinely nothing scheduled in the next seven days, or every calendar with upcoming events has been switched off in the iPhone app's Customize tab — the face shows SOME HIDDEN instead of NO EVENTS when that's the case, so you can tell them apart. Switch calendars back on in the iPhone app's Customize tab, under the Agenda face. An all-day event that has already started — a birthday, for instance — sorts behind your timed meetings, so the face keeps showing what is actually next; turn the Digital Crown to see it.
On the iPhone, open Customize, choose the Agenda face, and switch off any calendar you don't want. Everything starts switched on, and a calendar you add later appears automatically. The change syncs to the watch within a few seconds.
That screen needs calendar access on the iPhone itself — the watch's permission is separate. If you decline it, the picker is unavailable but the face on the watch carries on working.
One quirk worth knowing: if you rename a calendar, it becomes visible again, because LCD-84 remembers it by name. Switch it off once more and it stays hidden.
Decibel reads the sound measurements your watch already records, which means noise monitoring has to be switched on: on the iPhone, Watch app → Noise → Environmental Sound Measurements. It also needs health access on the watch, under Settings → Privacy & Security → Health → LCD-84.
It will not react to a clap, by design. The face never turns on the microphone — it charts the levels already recorded over recent hours, so the bars trend rather than jump. The dashed line sits at 80 dB, the level where sustained noise begins to damage hearing.
Open the iPhone app, tap any item marked PRO, then Restore Purchase on the sheet. The unlock is tied to your Apple Account and works on all your devices.
Tap the display for a 6-second EL glow. Key beeps and the backlight color are configurable in the iPhone app's Customize tab; Silent keeps the haptics without sound.
Email ppeltriaux@gmail.com — include your watchOS version and what you expected to happen.
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LCD-84 is an independent tribute to 80s digital watches and is not affiliated with Casio.