Standard disclaimer: I'm not a lawyer, but I have actually read about this stuff.
with sonic the hedghog being owned by sega.would i be infringing on copyright laws if i made one
Probably. Definitely, if you intend to use Sonic sprites ripped from an existing STH game. Also, since Sonic is Sega's de facto mascot, you may have problems with trademark laws also.
well ther'es no profit involved, so no i don't think so...
Profit is not required for infringement, though a finding of infringement is obviously more likely if profit is involved.
It all depends on whether Sega cares enough about it to bother.
This pretty much says it all. Copyright violation is nominally a civil offense rather than a criminal one, so it's up to Sega (or whoever they may have authorized, such as the IDSA or a law firm) to decide whether or not to take you to court for the infringement. However, since you intend to use Sonic, you could put Sega in a position in which they are obligated to sue you in order to maintain protection of any trademark protection Sonic might have (unlike copyright, trademark privileges can be lost if the trademark is not actively defended).
Any copyight laws applicable to Sonic the Hedgehog in the past are still applicable today. I would think that he(?) is covered by whatever goes in Japan. Unless they have laws that are completely different from the rest of the world, they will remain in effect until about 50 years after the death of his creator.
The basis for international copyright law is the Berne Convention for the Protection of Literary and Artistic Works, which requires all signatories to enforce foreign copyrights under their own laws, and sets a minimum copyright term of 50 years after the death of the author, or 50 years for anonymous/pseudonymous works, or works which are considered to have no natural author (Sonic probably falls into this category as a "work for hire" owned by Sega). In the United States, these terms were extended to 70 years after the author's death and 95 years, respectively, thanks to the Sonny Bono Copyright Term Extension Act
(sometimes referred to by its opponents
as the Mickey Mouse Protection Act, in reference to the fact that Congress seemingly has a habit of extending copyright terms whenever Steamboat Willie
's is about to expire).