Fire Alarm

Difficulty Level

Advanced

Introduction

While we don't recommend using our system as your main fire detection system, you can tap into your existing fire or smoke alarm system so that you can receive notifications on your phone when a fire alarm is detected.

What else do you need?

Tapping into an existing fire/smoke detection system is more advanced, and as such you will need some additional parts.

2.2k Ohm Resistors - Shop Amazon
10k Ohm Resistors - Shop Amazon
PC817 Octocoupler - Shop Amazon

Warning

While most sensors require 5V, the wiring diargram below requires you to use the 3.3V pin on either the Raspberry Pi or Arduino board. Using a 5V pin could damage your components.

Orange wire: Connect 3.3V from your Raspberry Pi to the collector pin (#4) on the PC817 IC.
Black wire: Connect GND on your board to a 2.2k Ohm resistor.
Yellow wire: Connect any GPIO pin on your Raspberry Pi to the other end of the 2.2k Ohm resistor.
Green wire: Connect the 2.2k Ohm resistor to the emmiter pin (#3) on the PC817 IC.
Gray wire: Connect the cathode pin (#2) to the GND on the fire/smoke detector.
Red wire: Connect the anode pin (#1) to a 10k Ohm resistor. Connect the other end of the resistor to the 9V (+) of the fire/smoke detector.

Orange wire: Connect 3.3V from your Arduino to the collector pin (#4) on the PC817 IC.
Black wire: Connect GND on your board to a 2.2k Ohm resistor.
Yellow wire: Connect any digital pin on your Arduino to the other end of the 2.2k Ohm resistor.
Green wire: Connect the 2.2k Ohm resistor to the emmiter pin (#3) on the PC817 IC.
Gray wire: Connect the cathode pin (#2) to the GND on the fire/smoke detector.
Red wire: Connect the anode pin (#1) to a 10k Ohm resistor. Connect the other end of the resistor to the 9V (+) of the fire/smoke detector.

Note

In this example, the main system board (Raspberry Pi) is connected to an expansion board (Arduino Mega) via I2C. See our tutorial on Expanion Boards for more details.