A very cheap and useful fire alarm system is presented below. The idea is to use simple temperature sensors and get an alert on building internal sirens and Telegram when the temperature in a room increases quickly.

As temperature sensors are commonly used in any room for climatization, no extra sensors are needed.

Fire alarm requirements

Temperature and humidity sensors for home automation systems

If you want to try our DomBusTH module, it integrates a temperature and relative humidity sensors, as like as RGW led, 4 I/Os, 2 outputs, in a small board that can be placed on a blank cover.

This is the perfect board to be placed in every room where temperature and humidity should be monitored for climate control. Through the 2 outputs it's possible to control 2 relays to open/close a shutter, for example. The 4 I/Os can be connected to alarm sensors (magnetic contact sensors applied to windows/doors, PIRs) or pushbuttons.
Also, using the script below it's possible to realize a fire alarm system that works also with this kind of temperature sensor.

The following video shows the DomBusTH module installed on a blank cover, measuring temperature and relative humidity, showing the current imported (red) or exported (green) power in kW, having a touch sensor used to select two different functions, and 6 I/Os (2 I/Os connected to a piezo buzzer).

Fire alarm script

On https://github.com/CreasolTech/domoticz_lua_scripts it's possible to find two scripts:

  • script_time_fireAlarm.lua , the script that check every minute the temperature on each room and verify that it does not increases to fast
  • config_fireAlarm.lua , the configuration file where it's possible to list all zones, defining the temperature device name and temperature increase rate.

Fire detection using Domoticz - Config file

When the temperature in a room increases, in 1 minute, more than the value specified for that room, a notification is sent to a Telegram group (or channel) and, optionally, one or more devices can be activated: for example it can activate the internal siren for few seconds, and the light in bedroom during the night.

Telegram notification for fire alarm detection system