If the router doesn't support scheduling itself, but otherwise does allow you to turn off the Wi-FI via the web interface (or change some other setting that wou

If the router doesn't support scheduling itself, but otherwise does allow you to turn off the Wi-FI via the web interface (or change some other setting that would achieve the desired effect of preventing internet access), you can always screen-scrape the web UI and automate it - run the resulting script on a scheduler on some machine that has access to the router.