Smoke Detector Problem? Driving me nuts!!!?

My smoke detector in my hallway has been going off for NO reason. No smoke, no nothing. I'm sure its a smoke detector and not a carbon monoxide detector. Three weeks ago it started to go off, and then it stopped. Today it went off with a single beep. A few minutes later, it emitted three beeps, then one. It just goes off at random times and is annoying the crap out of me. Can anyone tell me the problem?