Abstract: An outdoor alerting device for smoke alarms including an alarm detecting and alerting device drive unit and an exterior alerting device including a loudspeaker installed within a housing and a light display unit attached to the housing and having a light bulb. The alarm detecting and alerting device drive unit includes an alarm detection circuit including a microphone having a microphone output in electrical connection with an amplifier circuit for converting the audible alarm into an amplified electrical microphone signal. The amplified electrical microphone signal is then passed through a band pass filter that is tuned to the main audible output frequency of the audible alarm of the smoke detector to produce a filtered microphone signal. The filtered microphone signal is the passed through a rectifier circuit to convert the filtered microphone signal into a DC microphone signal. The DC microphone signal is then output to the signal input of a comparator.