E&TC / ECE · Robotics and drone · Mini project
Fire Detection and Alarm Mini
A mini fire alarm using a temperature sensor and a 555 timer. When the temperature rises sharply, the circuit sounds an alarm, giving early warning of fire.
What is the Fire Detection and Alarm Mini project?
A mini fire alarm using a temperature sensor and a 555 timer. When the temperature rises sharply, the circuit sounds an alarm, giving early warning of fire.
Key facts
- Branch
- Electronics & Telecommunication (E&TC / ECE); also suits Electrical
- Type
- Mini project · Beginner
- Suitable for
- Diploma micro-projects and B.E mini projects
- Build time
- 2 to 3 weeks
- Estimated component cost
- ₹2,300 – ₹3,300
- Guidance from
- ₹2,999 (Core Branch Mini Project)
How the Fire Detection and Alarm Mini works
- 12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V.
- The Temperature sensor measures the temperature that the system monitors or controls.
- The Push buttons and switches provide manual inputs and the power switch.
- The Arduino Uno R3 reads the inputs, runs the decision logic written in C/C++ and drives the outputs.
- The LEDs indicate status.
Block diagram
Inputs
Temperature sensorPush buttons and switchesController
Arduino Uno R3Outputs
LEDsComponents list and cost
Typical prices from Indian online stores and electronics markets (Lamington Road, Budhwar Peth, SP Road). Buy from one store where you can to save on shipping.
| Component | Qty | What it does | Approx. cost |
|---|---|---|---|
| Arduino Uno R3 | 1 | Reads the inputs, runs the decision logic written in C/C++ and drives the outputs. | ₹550 |
| Temperature sensor (LM35 / DS18B20) | 1 | Measures the temperature that the system monitors or controls. | ₹90 |
| Push buttons and switches | 2 | Provide manual inputs and the power switch. | ₹80 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| 12 V power adapter / step-down transformer | 1 | Supplies stable low-voltage power from the mains. | ₹250 |
| Passive components, PCB and wiring kit | 1 | Resistors (assorted), capacitors (assorted), transistors / MOSFETs, cables, connectors and jumper wires, diodes, PCB / breadboard and ICs and IC sockets. | ₹430 |
| Wiring, PCB, soldering and enclosure | 1 | Project overhead | ₹450 |
| Demo model base / mounting board | 1 | Project overhead | ₹500 |
| Testing spares and replacements | 1 | Project overhead | ₹300 |
| Estimated total | Varies with brand, quality and city | ₹2,300 – ₹3,300 |
Prices are estimates for budgeting. We confirm the bill of materials when your design is frozen, and components are charged at actual cost with bills.
How much does this project cost?
| Option | What you get | Cost |
|---|---|---|
| Components only | You buy the parts and build it yourself | ₹2,300 – ₹3,300 |
| Core Branch Mini Project | MATLAB / Proteus / CAD simulation files, Code, firmware or 2D drawings, Mini project report (20–30 pages) | ₹2,999 + components |
| Diploma Micro-Project | Micro-project report (10–15 pages), Relevant code, model or case study, MSBTE annexures | ₹899 + components |
No GST and no hidden charges. Use the cost calculator for a quote with your deadline and add-ons, or see all plans.
Download the project brief (PDF)
Summary, working, components and cost and viva questions on one branded PDF to show your guide or team. To get it developed, contact us on WhatsApp.
What you submit with this project
- Working model with circuit diagram and program code
- Project report or black book in your university's chapter order (block diagram, circuit, calculations, results)
- Presentation for the review and final viva
- Synopsis for topic approval, if your college asks for one
E&TC / ECE viva questions on this project
What is the aim of the Fire Detection and Alarm Mini project?
A mini fire alarm using a temperature sensor and a 555 timer. When the temperature rises sharply, the circuit sounds an alarm, giving early warning of fire.
Explain the working of your project in short.
12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V. The Temperature sensor measures the temperature that the system monitors or controls. The Push buttons and switches provide manual inputs and the power switch. The Arduino Uno R3 reads the inputs, runs the decision logic written in C/C++ and drives the outputs.
What microcontroller is on the Arduino Uno and what are its key specifications?
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.
How does the LM35 temperature sensor work?
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.
Why is a pull-up resistor needed with a push button?
Without it the input pin floats and reads random values. The pull-up keeps it HIGH until the button connects it to ground.
Why is a resistor connected in series with an LED?
It limits the current to a safe value (about 10–20 mA). Without it, the LED would draw too much current and burn out. R = (supply voltage − LED voltage) ÷ current.
How is 230 V AC converted to 5 V DC for the circuit?
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.
Explain the block diagram of your project.
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.
Which communication protocols are used between the modules?
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.
What is the operating voltage of the circuit?
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.
How did you calculate the power rating of your system?
Using P = V × I for each load, adding a margin of 20 to 25%.
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Want to build Fire Detection and Alarm Mini?
Send your college, deadline and team size. We confirm the scope, cost and what you will submit.