Setting a time based access control

Question

My teenage kids stay up too late, connected to our Tima Machine. I would like to set a timer so that the link is switched off at a certain hour. Can anyone please help me set that?

Answer 1

Are they logging on using a Mac?
If so, can't you just set up a new user account for them (not the same one that you, the administrator, uses and NOT an account with administrator rights) and then enable the parental controls and limit the logon time to the Mac?
system preferences > users and groups
click the padlock to make changes (assuming you have an administrator password for the main account - if not, set one)
enter your administrator password
create your user - make sure the account you create is NOT an administrator account (make sure the "allow user to administer this computer" option is not checked)
make sure the "enable parental controls" option is ticked
click "open parental controls"
click "time limits" on the top
do what you want to do (it is extremely flexible!)
click the lock to prevent further changes
That's it.
You can also use the tabs on the top to limit access to apps, websites, messaging, DVD burning etc etc. for whatever person is logged on as that user.
If they want to see how much time they have remaining, they can just click the menu bar clock (where the time is displayed) and a menu and readout will appear which says e.g. "Parental Controls: Time Remaining 1:05" or whatever is left.
If you set logon limits between, say 6:00 PM and 9:00 PM on weeknights, and they try and logon outside those parameters, a little message box will pop up which can be used to grant extra time - but it will require the administrator's password to authorise the extension.
As it gets to 9:00 PM they'll get a message telling them their time is almost up - with an option to grant more time.  Again, the administrator's password is required to authorise the extension.
Dealing with the tantrum is your problem ;-)
Works with Mountain Lion OS X 10.8.2
Note - that will limit the computer use altogether for that user account so if that user is connected via a Mac to Time Machine it'll work.
If they are not logging on through a Mac (e.g. they are using an iPad to connect to Time Machine) then I'm not sure - sorry.
I'm also not sure if you can limit Time Machine to times of the day - I think you can only do it by limiting the individual users - but would love to be proved wrong!
Good luck!
Hope that helps.