One good form of parental control is to limit the times in which an individual device can use the Internet. Basically, blocking the access to the public internet during the time-period selected.
This will require you to have the MAC address of the devices you wish to block. An easy way to obtain those is to look at the DHCP Leases list shown on the Overview page. It shows the name (if available), the IP and the MAC of connected devices.
If not immediately obvious, then go to the device and find out what IP address it’s using and then use that to look up the MAC on the DHCP leases list.
This is an advanced function and requires a visit to Advanced->Advanced Menu to start.
Then select Network->Firewall
Click on the Traffic Rules sub-tab
This will show you a long list of existing traffic rules.
We will be adding a new firewall rule per device we want to block.
Scroll down to the bottom of the page and in the New Forward rule section, type a name for this new rule and click ‘Add and edit …’
When the rule editor shows up, scroll to the Source MAC address control, and select the appropriate devices MAC from the drop-down list.
Scroll down and select ‘reject’ as the Destination Action
Scroll further and set the time at which you want the block to start taking effect in the ‘Start Time field’. Use 24hr notation. This example blocks from 20:00 (8pm) until 07:00 (7am).
Same for the end time, enter it in 24 hr notation.
NOTE: "00:00:00" is NOT a valid time entry, it will cause the rule to be ignored, if you want to specify midnight, use 23:59:00. Times are relative to the routers time, so make sure the time-zone is correct under System->System.
NOTE - 2: Firmware versions prior to v2.3 require that time be specified in UTC, so please add the offset necessary for your time zone (e.g +5 if on EST) AND check the UTC checkbox so it remains compatible with future firmware updates.
There are options to have the rule only apply on certain days or days of week. So you could have a rule that only blocked on weeknights. But the easiest is to just use the time windows.
Click ‘Save and Apply’
This is what the editor looks like just before the Save & Apply
Once done, it will look like this on the main list of Firewall rules:
Repeat for each device you want to block.
Finally, reboot the router by going to System->Reboot and click on 'Perform reboot'. The new rules should now be in effect.