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Classroom timer

05:00
00:00.00
    BOOM!
    00:30

    Space = start / pause · R = reset. Keep this tab in front so the alarm can play.

    How to use it

    A large, clear timer you can put on the board: a countdown for activities, a stopwatch with laps, and a bomb-fuse timer that makes a two-minute task feel like an event.

    1. Pick Countdown, Stopwatch or Bomb at the top.
    2. For a countdown, tap a preset (1, 2, 5, 10 minutes…) or type your own time, then press Start.
    3. Choose an alarm tone — it will sound when time is up. The screen turns red in the last ten seconds.
    4. Press Full screen to fill the projector; the space bar starts and pauses.

    Questions

    Does it keep running if I switch tabs?

    Yes — the timer is based on the clock, not on the tab being visible, so it stays accurate. Your browser may mute the alarm sound in a background tab, so keep it open in front for the final seconds.

    Will the screen go to sleep?

    While a timer is running the page asks your device to keep the screen awake (on browsers that support it).

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