Define "really efficient timer-based trigger mechanism". I use three ways of time-based triggering - alarmd, cron and asynchronous sleep(). The first one is good because AFAIK it can wake up the device even if it's turned off and uses almost no additional resources. Cron is, well, cron. Sleep() is far more precise and can be employed en masse if you can live with the resource penalty (we calculate when the event should occur and launch a thread that starts with sleep() at the beginning). If this does not answer you question, please elaborate