IoT Based Fire Department Alerting System

A system that alerts the fire department automatically over IoT. An Arduino reads fire and PIR sensors and, on detecting fire, sends the location and status to the fire department's web dashboard.

12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V. The PIR motion sensor detects human movement from the change in infrared heat. The Temperature sensor measures the temperature that the system monitors or controls. The Arduino Uno R3 reads the inputs, runs the decision logic written in C/C++ and drives the outputs.

The Uno uses the ATmega328P: 8-bit, 16 MHz clock, 32 KB flash, 2 KB SRAM, 14 digital I/O pins (6 PWM) and 6 analog inputs with a 10-bit ADC.

It has two pyroelectric elements that see infrared from different zones. When a warm body moves across them, the difference changes and the sensor gives a HIGH output.

LM35 gives an analog output of 10 mV per °C, so 250 mV means 25 °C. The controller reads it with the ADC and converts the value to degrees.

An active buzzer has a built-in oscillator and beeps on DC. A passive buzzer needs a square wave from the controller, which allows different tones.

A transformer steps down the voltage, a bridge rectifier converts AC to pulsating DC, a capacitor smooths it and a 7805 regulator gives a steady 5 V.

The input section senses the real-world quantity, the Arduino Uno R3 processes it according to the program, and the output section displays the result and drives the actuators. The power supply section feeds every block.

A single-wire digital protocol for the temperature sensor and analog inputs read by the ADC for the analog sensors. Each protocol was chosen because the module supports it and it uses the fewest pins.

The controller and most sensors work at 5 V (ESP boards and some modules at 3.3 V). A 12 V adapter powers the board, and a regulator steps it down. Motors and relays get their own supply line so they do not reset the controller.