Early game controllers were simple but most of the game consoles of the era (pre-NES) did not have wireless capability. Atari 2600 did have em but they were bulky, power guzzler, and probably no longer complies with current FCC rules.
I want to use Arduino to read controller inside (with battery) the switch contacts (5 for Atari 2600 and keypad matrix plus 2 or 3 buttons for Intellivision and Colecovision), send them over wireless to the console that has receiver and decode the signal into 7 or 8 pin connector for controllers (9th pin are always ground on the 3 consoles)
What is the right wireless module that is strictly one way, doesn't use existing internet or network but rather a emitter and receiver pair. Failing that IR LED but that'd require line of sight.