I don't think the home relays have worked for years. Nintendo shut down the backend servers at some point.
Nintendo had a deal with someone (att?) that all their free wifi hotspots would work as street pass relays. The way this worked under the hood is that your 3ds would see a wifi network named attwifi and then check the mac address of the ap, then it would report to Nintendo backend "hey, I just passed near mac xx:xx:xx:xx:xx:xx". Then Nintendo would note that down and also make it so the previous 3ds who visited that spot is now a street pass hit on your 3ds.
So, you would setup openwrt to broadcast a network named attwifi and make it switch every minute to a random mac from a list shared by everyone else doing this and you had yourself a guaranteed 10 hits a day (10 being the artificial limit Nintendo imposed).