This USB dongle will let you use your unmodified NES controllers on a computer. That’s because it includes the same socket you’d find on the classic console.
The image above shows the prototype. Instead of etching the copper clad board, each trace was milled by hand (presumably with a rotary tool). To the left the black square is made of several layers of electrical tape that builds the substrate up enough to fit snugly in a USB port.
An ATtiny45 running the V-USB stack has no problem reading the controller data and formatting it for use as a USB device. This is actually the second iteration of the project. The first attempt used an ATtiny44 and a free-formed circuit housed inside the controller. It worked quite well, but required alterations to the circuit board, and you needed to replace the stock connector with a USB plug. This dongle allows the controller to go unaltered so it can be used with an NES console again in the future.