I made such an adapter for myself...
viewtopic.php?f=25&t=25087&It's pretty straight forward to do.
grandta13 wrote:Where can I find the schematics for connecting an NES controller to the 15-pin port?
In the link that I posted above, I provided a link to a diagram that some one drew up on the famicom World forum.
grandta13 wrote:Would I be able to use a second extension cable to connect a second auxilarry controller (to work as Player 2)?
Absolutely. The Famicom's 15-pin port IS the two NES controller ports combined. Making such an adapter will give you two NES controller inputs, identical to what you'd have on an NES console.
grandta13 wrote:Are there any other controller types that are compatible with the NES, when wired correctly? If there are then I might consider making a modular connector to allow different controller types to be connected.
Do you mean to ask, are there any NES controllers that use something other than a NES controller plug? Not that I know of, I'm pretty sure not.
grandta13 wrote:Where can I get good quality extension cables without paying an arm and a leg? (They will need to be shipped to the US).
ebay. You can get them in pairs for cheap.
Example:
http://www.ebay.com/itm/2-NEW-6-FOOT-LO ... 27b3f7c83eThere's a few different ones on eBay, some better than others.
grandta13 wrote:Do you have any other advice you think I should hear before going into this project?
If you wanna make it look pretty, use a small project box. I have pictures of the adapter I made in the link I posted above. I wanted to avoid having a messy wad of electrical tape in the middle, so I came up with the box idea.
Another tip, if you use NES extension cables and a FC (or NeoGeo - since it's the same) extrension cable to make an adapter, you'll have the opposites ends of each cable left over. Don't discard them. They're good to make an adapter of the opposite function (use Famicom controllers on a NES console). When I made my first adapter, I was able to sell the unused ends to some one here on RB to make such an adapter for himself. He was very happy about it. I made myself a second NES-to-FC adapter, and thus made a second FC-to-NES adapter. It's been sitting in my BST thread for a while now. I guess it doesn't have high demand. But still, don't throw away the unused ends of the cables, they're perfectly good for other projects. Trade them away or something.
You don't actually have to make an adapter. You could remove the FC controllers from the console. On the FC console, the holes in the back where the controllers wires came out of, you could have some NES plugs coming out of there instead.
Definitely read through the thread I posted above. I threw out a lot of ideas I had. Also, there might be some useful info in the replies as well.
edit: I just noticed that the diagram image in the FC World link is down. No worries. I can make one and post it.