Some games for the Nintendo 3DS utilize / require Streetpass functionality to get the most enjoyment out of them. Unfortunately not everyone is in a position to actually utilize the Streetpass ability due to some people living in an area where there is no local Nintendo Hotspot available to them.
One of the ways to get streetpass visitors over the past couple of years has been to setup a Home Relay Station using a router capable of having custom software added to it. You would then clone your MAC address to one that another person also used for their Home Relay Station. Nintendo would think that you are near the same router that also has the same MAC address and would send you Streetpass data from random people who’s connected through that same MAC address in the past.
Now there is another way to setup a Home Relay Station. A software developer by the name of Matthew Hsu has released a program called PiPass, allowing you to turn your Raspberry Pi into a Nintendo Homepass Relay Station. The program is currently being hosted by GitHub and can be downloaded by visiting this link.