What can be wrong with the smoke detectors?

Question

The smoke detectors seem to always go off around the same time.The devices are reset from one bedroom and do not go off after that.

Answer 1

They all go off at the same time if they have been interconnected properly.  The bedroom one apparently is the culprit. Some combination of events or conditions causes it to false alarm.

If this is something that started recently, I suggest trying to clean it.  Blow it clean, take the vacuum cleaner to it, or follow the manufacturer's recommendation for cleaning.

If this doesn't do the trick I would replace the detector with a photoelectric type, compatible with the existing detectors.