Sensors in smoke detectors monitor how particles in the air affect a flow of current to the battery Garrett Aitken/iStock via Getty ImagesEditor’s note: MVS Chandrashekhar is a professor of electrical engineering at the University of South Carolina. In this interview, he explains how smoke detectors work and why they sometimes sound an alarm for what seems like no reason. Why do smoke detector alarms go off even when there’s no smoke? The most likely reason smoke detectors go off unexpectedly is