Timing a piratebox

Hi guys.
For an upcoming event, I need my pbox to go live automatically at a specific time, even better would be if it could also automatically turn off its service after the event. Is there any way to do so? My box is an MR-3020 and it needs to be powered by a battery, cable is not an option.
Thank you!
Tassilo

With battery, it is quite difficult.
I have an idea to add a script which automatically stops the wifi after running for 3h (or how long it should last). But starting at a particular time without additional intervention is hard, because you do not have valid/working date&time source on the MR3020.