Idea:

1. If there is smoke, smoke alarm detects it
2. ESP8266 detects this digital signal from smoke detector, connects to WiFi and sends data to a MQTT server
3. Esp8266 turns itself OFF

Implementation:

1. Try to find where on the smoke detector is the 3.3V digital signal when it detects smoke
   Lets look at Kiddie RF-SM-DC
   
   Third pin from top corner seems to send out 3.3V signal to speaker when it detects smoke
   
2. Lets connect our previously created ESP8266 circuit that wakes from external interrupt.
3. Configure Home Assistant to process MQTT message and send notifications.

Source code for this idea can be found on my GitHub: https://github.com/debsahu/Internet_Fire_Alarm