How to use LessonTimer
Everything below matches the app as it actually runs today, in beta. If a step doesn't match what you see, that's worth reporting — let us know.
Installing and opening it
LessonTimer runs on Linux, Windows and macOS. During beta you'll get a build directly, along with simple run instructions for your platform. There's nothing to install beyond that — no account, no sign‑in.
Setting up your class schedule
The Schedule table is the heart of the app. Each row is a class period, and every time is a clock time — when it starts and when it ends — not a duration you have to do the math on.
- Click Add to create a period: give it a label (e.g. “P1 — Class time”), a start time, and how long it runs.
- Pick which days it applies to — Monday to Friday by default, or any combination.
- A duration of 0 makes it a cue‑only entry — a sound at a specific time with no countdown on screen, useful for a plain bell.
- Turn on “Resume mid‑flight if the machine was asleep” so a closed laptop lid doesn't throw off the end time — this is on by default and is the whole reason the app exists.
Select any row and click Edit to change it, or Remove to delete it.
Different schedules for different days
Monday's schedule usually isn't Wednesday's. The Day dropdown at the top of the Schedule section switches between saved day profiles — each with its own independent list of periods.
- New day starts a blank profile; Duplicate copies the currently selected one so you can tweak just what's different.
- Only one profile is active at a time — that's the one being watched for the day's cues.
- The Scheduling on checkbox turns the whole schedule off temporarily (a holiday, an assembly day) without deleting anything.
Quick timers and cue points
The Quick timers row above the schedule is for on‑the‑fly timers you start by clicking a button — sight reading, a warm‑up, a sectional. Click + Save a timer to add one.
- Give it a name and a length in minutes — up to 24 hours.
- Say yes to “Add cue points?” to have it fire extra alerts partway through, at whatever minute marks you choose — as many as you like. A 50‑minute timer with a warning at 4 minutes and another at 47 is one saved timer, not three.
- Choose whether it should keep counting upward past zero (
+MM:SS) instead of stopping — handy for the last period of the day, when nothing's scheduled right after it.
Right‑click any quick timer to delete it.
Sounds, repeat, and volume
Every period and every quick timer picks its own sound, how many times it repeats, and how loud it is — so “class starts” and “pack up” never sound the same.
- Five built‑in tones, including a soft single beep for a quiet room.
- Or choose “Custom sound…” to browse for your own recording — a real school bell, for instance.
- The Preview button plays your current choice before you save, at the volume you've set.
Projecting to the room
Click Fullscreen (or press F11) to switch the countdown to a full‑screen display sized for a projector — the digits scale up as the window grows, and stay large enough to read from the back of the room. Press Escape to exit.
When a timer hits zero, the display flashes briefly on top of the usual colour change — visible even if the room's too loud to hear the cue.
Stopping or resetting a timer
A Reset button appears next to the countdown any time a timer is running — click it to cancel early, or to dismiss one that's counting upward past zero. It only ever affects the timer currently shown large; a second timer running in the background underneath it is left alone.
Starting automatically
Tick “Start with my computer” to have LessonTimer open automatically when you log in — no admin rights needed, works the same way on a school-managed machine as on your own. If your desktop doesn't show a tray icon (some Linux setups don't by default), the app keeps its window open instead of hiding, so a running schedule is never stranded somewhere you can't find it.