Understand this. You don't have to sign a contract to have a contract. The minute your "roommate" hands you money (or anything of value) in exchange for living there, no matter how you spin it, he/she is your "tenant" and you are his/her "landlord" and you have a "rental agreement" (contract).
Granted, it's an informal (oral) contract but the upshot is that you are still renting out part of your condo and (trust me on this) any roommate you find will expect that the arrangement (again, no matter how you spin it) will be governed by applicable landlord tenant law.
Another thing: when your roommate starts parking his/her car in the HOA parking areas and uses his/her key to access HOA facilities, questions will be raised and that board member will have amnesia about the statement that you can have a roommate.
I also suggest you google something like "roommate horror stories" and learn why it's an incredibly bad idea to have one.

