Open Google's Play Store app.
Click on the search icon.
Enter the word Emulator.
Realize that there are probably hundreds there (see
https://play.google.com/store/search?q=emulator&c=apps if you want to check them on your PC first).
Narrow down the search by entering the console/handheld/early computer's model name as well as emulator.
Which controller? You can use your IR remote control (not ideal...), a VIP remote control, a USB keyboard, an xBox 360 wireless controller (if you have the USB adaptor for a PC), bluetooth gamepads. Some emulators will allow you to remap buttons to more closely follow the original button layout.
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Or just a normal USB gamepad/joystick.
I've not tried my steering wheel yet, don't know how well Android devices would handle the analogue left/right of a wheel and the pedals etc