I constructed it in my head when I was in college. I think lots of people do that; it's not a very complicated idea at all. It's just that some people wrote it down and their writings somehow became famous.

When I constructed a similar argument, it was simply an argument I was having in my head with an imaginary person who was arguing with me that computers can have perception just like humans.

A homunculus is a homunculus, but nevertheless Searle's Chinese Room is perhaps a bit more radical - not so much conceptually but rather because it was proposed in contradiction to a well entrenched belief system - behaviorism.