Game cube to usb adapter advice

[fishys182]

I am currently trying to help my boyfriend figure out something. his project is to design and build a game cube to usb adapter that will work with stepmania (a dance dance revolution simulator that you can download for free online). he has already correctly mapped out the buttons in his code, but now needs to have stepmania be able to read serial data. does anyone know how to go about this?

 

[K.J.Healey]

So you have the data acquisition part done right? You can get the signal from the gamecube control part, but you need to then use that to control the game's controls? Or is it the other way around.