Wake up from the sleep?

Hi.
I know that we can block the device from powersave by writing to /sys/power/wake_lock, but can we do the opposite and force it to sleep with a timer set to wake up the device after some period of time?

The main idea is to write a script that wakes up the device periodically to download some data and, possibly, display it on the screen. This way, the device could be used to display agenda in a conference room for much longer than with the sleep disabled.

What do you think?