My smoke alarms have been bleeping periodically overnight, approximately every thirty seconds, but not all night (if you see what I mean). They are connected to the mains so it is not a battery problem. We have pressed the reset buttons but this does not seem to have any effect The green light is on and overnight the red light was on but it is off now in spite of the bleeping continuing.
I had a similar problem in my old place, the alarm would suddenly go off in the middle of the night. Turns out condensation was the problem - as soon as I left a window or two ajar over night I didn't get the problem any more.
Consult the owner/user manual – or if lost, the manufacturer to discover the meaning of the audible/visual signals given off by the alarms.
Bear in mind that most smoke alarms have a recommended life of 10 years and they may require replacement. It would be cold comfort to have saved money on the smoke alarms, versus property fire damage or worse.