Published April 14, 2019 © GPL3+

MEGR 3171 Fire Detector

Uses 2 Particle Photons to detect flames via an IR sensor and transmit the data.

BeginnerFull instructions provided1 hour857

Things used in this project

Hardware components

Particle Photon

Buzzer

Active Buzzer from Arduino sensor kit

Flame Sensor

5 mm LED: Red

LED, Blue

Resistor

Any Resistor value should work

Jumper wires (generic)

Software apps and online services

Particle Build Web IDE

Story

My apartment has a really crappy fire alarm system that gets fasely triggered all the time. It even gets activated when boiling water! These fire alarms are based on gas particles and the saying "If there's smoke, there's fire." But I wanted something a little more relaxed.

This fire alarm is based off an Infrared detector. This means it will only get activated by things like sunlight and hot objects.

First off, lets build the detector circuit. It requires 1 Photon, 1 Flame sensor, 1 Red LED, 1 Active Buzzer, and 5 Jumper Wires. Below is the wiring schematic for the circuit.

Fire Detection Circuit (Photon Image taken from: https://www.dineshjoshi.com/2017/07/offline-toolchain-particle-photon-electron/)

The code for this photon is fairly simple, as seen below.

Fire Detect Photon Code

Note on line 22 and 33, the value of 2900 was detemined through testing the Flame sensor with a lighter and by pointing it at the sun. Calibrating it this way should eliminate false positives. Using the Potentiometer on the Flame Detector, you can also fine tune how sensitive the sensor is to signals like sunlight and cellphone batteries. For my model, turning the screw CCW decreases the sensitivity. (Upon further testing, it is the phone's camera, not the battery making the sensor activate.)

The code simply states:

If we detect a fire, and there wasnt a fire before, to turn on the LED indicator and activate the buzzer.
If there was a fire before, but we don't detect one now, turn off the LED and the buzzer
If there is a fire currently, but we recieve a signal from the other photon to turn off the buzzer, turn off the buzzer.

Of course, all the pins and variable names can be changed to best suit your needs. When naming Particle.Publish Events, make sure to only use letters, numbers, "\", "/", "-", and "_". Anything else will make the events not work properly.

Now that the detector is set up, lets buld the receiver.

The receiver uses 1 Photon, 1 Button, 1 Resistor (any resistance should work), 1 Red LED, 1 Blue LED, and 3 Jumper Wires. Follow the schematic below to build the receiver.

Receiver Circuit

And the code for the receiver is:

Receiver Code

This code does the following:

Reads Alert messages from the Fire Detector and sets its status LED accordingly.
Checks if the button is pressed. If it is, it sends a message to the Fire Detector to turn the buzzer off.

The best part about this fire detector is the ability to turn the annoying buzzer off.

Using ThingSpeak and Particle's Webhooks, I was able to graph the detect value from the detector in real time. My version doesn't say when the fire went off (not for lack of trying), but it does let you see how intense the signal was. In the case of this sensor, a lower value means a hotter object, which can be seen in the code for the detector.

You can follow this link to learn how to set up your own webhooks. It's super easy!

https://docs.particle.io/tutorials/device-cloud/webhooks/

ThingSpeak Data Plotting in Real Time

Use the link below to view Live Data.

https://thingspeak.com/channels/758135

Here is a picture of the detector in action. The Red LED indicating that a flame is detected.

Flame Detector in Action

Code

int sensor = A5;        //Pin Declaration
int alarm = D6;         //Pin Declaration
int status = D7;        //Pin Declaration

int detect = 0;         //Pin Data

bool fire = false;      //Flag
bool buzz = false;      //Flag

void setup() {
    Serial.begin(9600);                                         //Has to do with hardware ports
    pinMode(sensor, INPUT);                                     //Pin Setup
    pinMode(alarm, OUTPUT);                                     //Pin Setup
    pinMode(status, OUTPUT);                                    //Pin Setup
    Particle.subscribe("alarmoff", buzzOff, MY_DEVICES);        //Listen for Alarm Off
    Particle.variable("detect", detect);                        //allows me to read the value of detect from CMD prompt
}

void loop() {
    detect = analogRead(sensor);                                //Get input from sensor
    if(detect <= 2900 && fire == false){                        //If sensor reads fire and there wasn't a fire last clock cycle
        String num = String(detect);                            //Converts int to string so it can be published
        digitalWrite(alarm, HIGH);                              //Turn on the alarm
        digitalWrite(status, HIGH);                             //Turn on the D7 LED
        fire = true;                                            //Set the Fire Flag to True
        Particle.publish("Fire_Detected", "fire", PRIVATE);     //Let the other Particle know there was a fire
        Particle.publish("Fire_Value", num, PRIVATE);           //Give ThingSpeak a value to graph
        delay(2000);                                            //Prevents overflow of publish events
    }else if(buzz == true && fire == true){                     //If there is still a fire and you have been told to buzz off
        digitalWrite(alarm, LOW);                               //Turn off the alarm
        buzz = false;
    }
    
    if(fire == true && detect >= 2900){                         //If no fire
        Particle.publish("Fire_Detected", "nofire", PRIVATE);   //Let the other Particle know there was a fire
        digitalWrite(alarm, LOW);                               //Turn off the alarm
        digitalWrite(status, LOW);                              //Turn off the D7 LED
        fire = false;                                           //Set the Fire Flag to False
    }
}

void buzzOff(const char *event, const char *data){              //Function that runs when an "alarmoff" event is published
    if(strcmp(data, "off") == 0){                               //If the event was published
        buzz = true;                                            //Set Flag of buzz to True
    }    
}

int status = D7;        //Pin Declaration
int press = D6;         //Pin Declaration

bool actnow = false;    //Flag

void setup() {
    Particle.subscribe("Fire_Detected", panicMode, MY_DEVICES);   //Subscribe to the other photon to get fire info
    pinMode(status, OUTPUT);
    pinMode(press, INPUT);
    Serial.begin(9600);                                           //Has to do with hardware ports
}

void loop() {
    if(actnow == true && digitalRead(press) == HIGH){
        Particle.publish("alarmoff", "off", PRIVATE);             //Let the other Particle know we aknowledged the fire
        delay(2000);
    }
}

void panicMode(const char *event, const char *data){              //Function that runs when an "alarmoff" event is published
    if(strcmp(data,"fire") == 0){                                 //If the event data "fire" was published
        actnow = true;                                            //Set Flag to True
        digitalWrite(status, HIGH);                               //Turn on LED
    }else if(strcmp(data,"nofire") == 0){                         //Else if "nofire" was published
        actnow = false;                                           //Set Flag to false
        digitalWrite(status, LOW);                                //Turn off LED
    }   
}

Credits

Garrett Colby

1 project • 1 follower

MEGR 3171 Fire Detector

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Detector Schematic

Receiver Schematic

Code

Detector Code

Receiver Code

Credits

Garrett Colby

Comments

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MEGR 3171 Fire Detector

MEGR 3171 Fire Detector

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Detector Schematic

Receiver Schematic

Code

Detector Code

Receiver Code

Credits

Garrett Colby

Comments

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