How can I create two separate, isolated wifi networks with one Internet connection/modem? My scenario:


I just got a "smart" sprinkler device that needs to connect to the internet over WiFi
I do not want to put that device on the same network as my other Internet-connected Macs and devices in the home
I have one Airport Time Capsule and one Airport Extreme
I also have an unmanaged gigabit switch
I have Comcast cable Internet service with one cable modem. I don't think I have a static IP from Comcast.


Question(s):


Is it possible with the equipment I have to create two separate WiFi networks that can't see each other?
If so, would that be adequate protection for my Macs and home devices if the smart sprinkler somehow got hacked?
If yes to both of the above, how do I set it up?


So far, I've been able to create two WiFi networks, but haven't been able to get them both connected to the Internet without them obviously sharing the same underlying network. For example, I can print from WiFi network #1 to the wireless printer attached to WiFi network #2.

Any thoughts?
Apple networks do this well with the guest network. All the "suspect" devices only get to go to the internet and not infect / snoop / attack the trusted machines on the proper network. Many other network vendors have the same idea - either by making separate VLAN for the sequestered / DMZ devices as needed.

It doesn't make sense to address each of the separate questions since each would be a long several paragraphs. Perhaps narrow down on one item once you've chosen to set up your network and can document it and ask the subquestion with details needed for a more narrow answer.