org-tempus

Org Tempus augments Org's native time tracking capabilities by
setting customizable thresholds for a session, and computing the
total clocked time in a day.  The package will optionally send
notifications when thresholds are reached.  It can also detect
activity and auto clock in to a default task, or auto clock out
when idle.  The idle detection mechanism supports multiple sources,
such as Emacs itself, Mutter (for GNOME), and freedesktop.org
ScreenSaver.  Additionally, all the logged time and thresholds are
displayed in the mode line.  This information can optionally be
sent somewhere else (such as dconf, to integrate with a GNOME
desktop environment, for example).