When Raspberry Pi mini computers were released, many called an all in one retro game console. With the use of a raspberry Pi you can build an emulator box for NES games. What you want to achieve in this project is to enable the emulator box to play NES/SNES games by using the original NES controller and case.
Take the NES and carefully remove the screws so you can take it apart. Next, take the raspberry pi B with a power circuit and position it inside the case. Leave the original power and reset button/LED because you will still be using this. This LED is connected to the power and ground GPIO pins found on the pi.
To keep the HDMI and the micro USB in place, it needs to be hot glued unto the opening of the NES case.
Keep the cables from the original reset and power buttons connected to it. This will allow reboot of the pi by pushing the power button. The moment the power button is pressed it relays command to the pi so it shuts down through GPIO thus cutting the power supply.
Another thing you need is a USB hub that you will use for the controller. You can buy this at a cheap price in amazon. You need to mount the USB on top of inside making it accessible from the game loading door. Connect the controllers before closing the case and testing and playing.
See more pictures at: http://imgur.com/a/o5vjL