Some alarms will go off automatically if they detect smoke, an intruder, a low room temperature or if the individual hasn't moved in a while.

A host of sensors detects acceleration, deceleration, tilt, temperature and smoke.

A smoke detector is a device that detects smoke and issues a signal.

Odo wished he had a sense of smell, so he could detect smoke if a fire broke out.

Aspirating smoke detectors can detect smoke before it is visible to the human eye.

He detected smoke in the first lungful of air.

A smoke detector is a device that detects smoke, typically as an indicator of fire.

This provides sufficient ion current to detect smoke, while producing a very low level of radiation outside the device.

There was an expressway exit ramp ahead and he detected smoke, he thought, rising from the road near it.

He stomped out the door, and a keen nose would have detected smoke coming from his ears.