I'm working on putting the parts together for this, and just a FYI that it's not necessarily an inexpensive project to put together. I haven't started on the assembly yet, but so far I have almost $150 into it. My total is below. The unit is going to have more functionality than I can get from spending a $150 on anything else and so I'm fine with spending the money, but if you think it's an inexpensive controller that's not quite the case.
Raspberry Pi $45.00 - WiFi Adapter $10 - PCB $13 - Mouser and Digikey parts $80 - Total$148.00