E&TC / ECE · Robotics and drone · Final year project
Alcohol Sensing Display With Alarm
A breath alcohol tester that displays the alcohol level and sounds an alarm above a limit. An MQ-3 sensor's analog output is read by a microcontroller, converted to a percentage, shown on an LCD and compared with the threshold.
What is the Alcohol Sensing Display With Alarm project?
A breath alcohol tester that displays the alcohol level and sounds an alarm above a limit. An MQ-3 sensor's analog output is read by a microcontroller, converted to a percentage, shown on an LCD and compared with the threshold.
Key facts
- Branch
- Electronics & Telecommunication (E&TC / ECE); also suits Instrumentation
- 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
- ₹2,200 – ₹3,200
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Alcohol Sensing Display With Alarm works
- 12 V power adapter / step-down transformer 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 ATmega328P microcontroller with base board is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs.
- The Buzzer gives an audible alert.
- The LEDs indicate status.
Block diagram
Inputs
Push buttons and switchesController
ATmega328P microcontroller with base boardOutputs
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 |
|---|---|---|---|
| ATmega328P microcontroller with base board | 1 | Is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs. | ₹350 |
| 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 |
| 12 V power adapter / step-down transformer | 1 | Supplies stable low-voltage power from the mains. | ₹250 |
| MQ 3 Alcohol Ethanol Sensor | 1 | Part from the design specification | ₹150* |
| Passive components, PCB and wiring kit | 1 | Crystal oscillator, resistors (assorted), capacitors (assorted), transistors / MOSFETs, cables, connectors and jumper wires, diodes, PCB / breadboard and ICs and IC sockets. | ₹445 |
| 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 | ₹2,200 – ₹3,200 |
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 | ₹2,200 – ₹3,200 |
| 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 Alcohol Sensing Display With Alarm project?
A breath alcohol tester that displays the alcohol level and sounds an alarm above a limit. An MQ-3 sensor's analog output is read by a microcontroller, converted to a percentage, shown on an LCD and compared with the threshold.
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 Push buttons and switches provide manual inputs and the power switch. The ATmega328P microcontroller with base board is the brain of the circuit: it samples the sensors, compares readings with set limits and switches the outputs. The Buzzer gives an audible alert.
Why is a microcontroller used in this project?
A microcontroller combines a CPU, memory and I/O pins on one chip, so a single low-cost IC can read sensors, make decisions in code and control loads without a computer.
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 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 ATmega328P microcontroller with base board 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). 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.
What is the difference between accuracy and precision?
Accuracy is how close a reading is to the true value. Precision is how close repeated readings are to each other. A sensor can be precise but inaccurate if it is not calibrated.
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