E&TC / ECE · Robotics and drone · Final year project
Automatic Smoke Detector Alarm
A low-cost smoke alarm that uses infrared light instead of expensive smoke sensors. An IR transmitter and receiver face each other; when smoke blocks the beam, the circuit sounds an alarm to warn people of fire.
What is the Automatic Smoke Detector Alarm project?
A low-cost smoke alarm that uses infrared light instead of expensive smoke sensors. An IR transmitter and receiver face each other; when smoke blocks the beam, the circuit sounds an alarm to warn people of fire.
Key facts
- Branch
- Electronics & Telecommunication (E&TC / ECE); also suits Electrical
- Type
- Final year project · Intermediate
- Suitable for
- Diploma capstone and B.E / B.Tech final year
- Build time
- 4 to 6 weeks
- Estimated component cost
- ₹2,700 – ₹3,900
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Automatic Smoke Detector Alarm works
- Rechargeable battery supplies the circuit; a regulator gives the controller and sensors a steady 5 V.
- 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 Buzzer gives an audible alert.
- The LEDs indicate status.
Block diagram
Inputs
Push buttons and switchesController
Arduino Uno R3Outputs
BuzzerLEDsComponents 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 |
| Push buttons and switches | 2 | Provide manual inputs and the power switch. | ₹80 |
| Buzzer | 1 | Gives an audible alert. | ₹20 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| Rechargeable battery (12 V 1.3–7 Ah) | 1 | Stores energy and supplies power when mains is absent. | ₹650 |
| I R Transmitter Receiver | 1 | Part from the design specification | ₹150* |
| Passive components, PCB and wiring kit | 1 | ICs and IC sockets, resistors (assorted), capacitors (assorted), transistors / MOSFETs, cables, connectors and jumper wires, diodes and PCB / breadboard. | ₹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 | ₹2,700 – ₹3,900 |
Prices are estimates for budgeting; items marked * depend on the exact size or model chosen. 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 | ₹2,700 – ₹3,900 |
| Hardware / IoT Final Year | Working model or guided build, Circuit diagram and bill of materials, Firmware / code with explanation | from ₹9,999 + components |
| Capstone Project (CPE) | Working project or model, Black book in MSBTE format, Step-by-step explanation | ₹9,999 + components |
| Diploma ITR | 100% working source code, Project report PDF, PPT | ₹1,999 + 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 Automatic Smoke Detector Alarm project?
A low-cost smoke alarm that uses infrared light instead of expensive smoke sensors. An IR transmitter and receiver face each other; when smoke blocks the beam, the circuit sounds an alarm to warn people of fire.
Explain the working of your project in short.
Rechargeable battery supplies the circuit; a regulator gives the controller and sensors a steady 5 V. 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 Buzzer gives an audible alert.
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.
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.
What is the difference between an active and a passive buzzer?
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.
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 do you calculate battery backup time?
Backup time (hours) ≈ battery capacity (Ah) × voltage × 0.8 efficiency ÷ load power (W). For example, 12 V 7 Ah at 20 W gives about 3.3 hours.
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?
The sensors give digital or analog signals read directly by the controller's I/O and ADC pins, and outputs are driven through transistor or relay drivers.
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). The battery 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%. Battery capacity is the energy needed per day divided by the battery voltage and allowable depth of discharge.
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Want to build Automatic Smoke Detector Alarm?
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