The Hombli Smarter smoke detector works on the principle of smoke detection using an optoelectronic sensor. This sensor detects smoke and triggers a loud alarm of over 85 dB when it is detected.

Regarding the battery warning: When the battery is empty, the detector will emit a warning, but the exact duration of the beeping is not specified in the sources provided. However, it is common for such devices to warn repeatedly over an extended period of time until the battery is replaced.