Quantity   Component name
1 × Raspberry Pi Model B
2 × 16x opto-isolated relay board (ebay, ~$15)
2 × mcp23017 Microprocessors, Microcontrollers, DSPs / IO Controllers
1 × 5v regulator going to try to use one of those in-car dealies, but might need something beefier
1 × Car battery yes yes, deep cycle marine yadda yadda, but I have one of these
1 × lot of wire Resistors (Fixed) / Zero Ohm Jumpers
1 × either a wireless router, or a wifi dongle for the rpi