We have featured many nice game controllers for Android phones and tablets, but if you like to do something by yourself, the following Game Boy game controller may be able to draw your more attention.
Alpinedelta, a member of instructables created the amazing game controller using a Wii remote as the Bluetooth interface, and a Dot Matrix Gameboy’s buttons and shell. As we can see from the images, the display of the Gameboy has been replaced by a phone case in order to hold the smartphone. The maker has tried with a SNES emulator, but using the “Wii Controller IME” app, the Game Boy game controller will control anything which lets you use the Android touch keyboard as input, and in theory you can play many mobile games with the D-pad and two buttons. The maker has released the whole steps. If you also want to build one with your retro GameBoy, jump to instructables for more details or check out the following demo video first.
Additionally, if you need other options, you might like to check iDroid game controller and more via “game controller” tag.