So, as far as I can tell there are no real digital inputs for the FBV4. Granted, you could use the analog inputs, but then unless you hit the button, your signal is floating which makes for a bad reading, and you can only use the +5v that is coming out of the board to switch it. I don't know about you, but the idea of the pins from the microchip being attached to wires running the length of my car with no protection whatsoever kinda worries me. With that in mind, I came up with the image posted below.
This board clips onto the Fusion Brain V4 via female 0.1" header connectors on the bottom of the board. It brings the Digital Outputs and Analog Inputs through, and if you put a jumper between the extra rows of pins that are on the top of the board, you can then use 12 of the 13 analog inputs as digital inputs. They will be tied to +5, and applying from 0-20 volts to the input headers (the two 2x6 headers) will bring that to ground. Voila, now you just have to test the analog input for being above or below 2.5volts, and it should have no interferance problems. The inputs are optoisolated to prevent overvolting your analog outputs, so you can use regular car power in theory, I may wind up adding some smoothing capacitors.
When jumpers are in place. each jumper will draw 227 microamps (thats 0.0002 amps or 0.2 milliamps) off the +5 volt rail of the Fusion Brain. I figured it had enough current to handle that
Anyway, I figured I'd see if there was interest in something like this, if so I'll post board schematics and layout later today. Any thoughts/comments/criticisms?
Oh, and I'm aware the size dosent quite match the FB, there is plenty of room to make it match once I find my caliper and get more precise measurements on where the headers are