If you can find a suitable joystick from game consoles before the xbox and ps3, all that stuff uses something like SPI interfaces or shift registers to communicate with the console, which is much easier to work with from a digispark point of view. Old PC joysticks that used the midi/joystick soundcard port aren't very suitable though as they do not have a digital interface, and some of the atari/amega era joysticks and gamepads also do not use a digital interface. Things like NES controllers are shift registers, PS1 and PS2 controllers are SPI, while dreamcast controllers use serial through a weird
proprietary serial protocol, as do
gamecube and n64 controllers. Anything which plugs in to the bottom of a wii remote is i2c based. at worst these digital interfaces require four pins, which leaves two spare on a digispark - one of which can act as your output for PPM signalling. The wii nunchuck is a kinda neat controller because it has an analog stick, two buttons, and a three axis accelerometer via a simple digital interface.
