Hey everyone, since my first attempt at making one of these seemed to go fine, I'm willing to assemble more of these if other people want one.
Rather than asking numerous people online to buy and ship items to me for assembly, I can order the materials myself if you can pay me back for them. If there are several people who really want one, I'd prefer to order all the parts at once to save on shipping fees.
I want you to make me one!If you want me to assemble one of these for you, I'd expect you to reimburse me for at least the cost of acquiring all the materials plus the cost to ship the finished product to you. If I was making just one of them at a time, the least I can seem to pay to get all the parts to me (including retailer shipping costs) is about $30 (USD). Shipping it to you would probably be somewhere in the neighborhood of $5 if you are in the USA, probably closer to $10 for Canada, and I have no idea about anything beyond that.
I'll plan to make an order for all these parts 10 days from now (19 November). If you want me to make you one, please clearly post in this thread something like
Please make one of these for me, I [need/don't need] a micro USB cable as well
before that date.
I want more details so I can make my own!Here is the list of parts I used to make the first one (prices in USD). If you have better suggestions for any of these ($ savings or quality upgrade), please share!
Mini ATmega328 board w/USB onboard - $15
2" x 1" x 0.5" plastic enclosure - $2.50
N64 controller extension cable (2m) - $7
Here is a photo showing these three components so you get an idea of how big everything is and how it fits together. Also see the video
here.

Then just a few assorted bits of wire and such to put it together.
How do I use it?For reference, the software that this device is designed for is called
NintendoSpy. That project is capable of interfacing with several gaming systems, but the adapter I made is specifically for N64 (mainly because it is integrated into the extension cable directly).
I decided the most straightforward approach would be to just use a standard microcontroller board with built in USB chip to simplify my work. I'm sure you could get this to run on a somewhat cheaper microcontroller, but you also need a simple USB connection so this fits about perfectly. Most smaller boards don't have USB communications enabled out of the box. Fortunately, the mini size boards are cheaper than the full size arduino devices anyway.
If you don't have one already, you will also need a micro USB cable to connect the box to your computer. Basically any micro USB to "normal" USB cable should work.
Here is an example if you have no idea what I'm talking about. I assume most people at least have one of these because they are used to charge numerous electronic devices made in the last several years. If you want another one specifically for use with this adapter, I can get one and send it with for you as well. They cost somewhere in the neighborhood of $5 and come in lengths of 1m, 2m, 3m or so.