Mechanical · Pneumatic and hydraulic · Final year project
Automatic Knock Detector Pneumatic Door Opener Using Piezo
A door that opens when you knock. A piezo vibration sensor detects the knock pattern, and an ATmega328 operates pneumatic cylinders to swing the door open hands-free.
What is the Automatic Knock Detector Pneumatic Door Opener Using Piezo project?
A door that opens when you knock. A piezo vibration sensor detects the knock pattern, and an ATmega328 operates pneumatic cylinders to swing the door open hands-free.
Key facts
- Branch
- Mechanical & Automobile Engineering; also suits Mechatronics
- Type
- Final year project · Advanced
- Suitable for
- Diploma capstone and B.E / B.Tech final year
- Build time
- 6 to 8 weeks
- Estimated component cost
- ₹12,700 – ₹18,700
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Automatic Knock Detector Pneumatic Door Opener Using Piezo works
- The mild steel frame and fabrication forms the base that carries every other part, so it is designed first from the load and size of the machine.
- The Pneumatic cylinder converts compressed air into linear push-pull motion.
- The Air compressor supplies compressed air.
- The Wheels / castor wheels allow the machine or vehicle to move.
- 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 Solenoid lock locks or unlocks the door when energised.
Block diagram
Power
Solenoid lockPiezoelectric discsPneumatic cylinderWorking unit
Pneumatic cylinderAir compressor (small)Wheels / castor wheelsStructure
Frame and mountsComponents 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 |
| Solenoid lock (12 V) | 1 | Locks or unlocks the door when energised. | ₹450 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| Piezoelectric discs (set) | 1 | Generate a small voltage when pressed, used for energy harvesting. | ₹250 |
| Pneumatic cylinder | 1 | Converts compressed air into linear push-pull motion. | ₹1,800 |
| Mild steel frame and fabrication | 1 | Forms the main structure that holds all parts. | ₹2,500 |
| Air compressor (small) | 1 | Supplies compressed air. | ₹3,500 |
| Wheels / castor wheels | 1 | Allow the machine or vehicle to move. | ₹400 |
| FRL unit (filter-regulator-lubricator) | 1 | Needed for this type of build. | ₹1,500 |
| PU pipes and push-in fittings | 1 | Needed for this type of build. | ₹700 |
| Welding, cutting and machining labour | 1 | Needed for this type of build. | ₹2,200 |
| Mounts, screws, nuts and small hardware | 1 | Enclosure, mounts and fasteners. | ₹300 |
| Paint, finishing and workshop consumables | 1 | Project overhead | ₹600 |
| Transport of material | 1 | Project overhead | ₹400 |
| Estimated total | Varies with brand, quality and city | ₹12,700 – ₹18,700 |
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 | ₹12,700 – ₹18,700 |
| 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
Mechanical viva questions on this project
What is the aim of the Automatic Knock Detector Pneumatic Door Opener Using Piezo project?
A door that opens when you knock. A piezo vibration sensor detects the knock pattern, and an ATmega328 operates pneumatic cylinders to swing the door open hands-free.
Explain the working of your project in short.
The mild steel frame and fabrication forms the base that carries every other part, so it is designed first from the load and size of the machine. The Pneumatic cylinder converts compressed air into linear push-pull motion. The Air compressor supplies compressed air. The Wheels / castor wheels allow the machine or vehicle to move.
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.
How does a solenoid lock work?
When current flows, the coil becomes an electromagnet and pulls the plunger in, releasing the latch. When current stops, the spring pushes the plunger back to lock.
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.
What is the piezoelectric effect?
Certain crystals such as PZT produce an electric charge when mechanically stressed. Each press gives a small AC pulse that is rectified and stored in a capacitor or battery.
What is the difference between single-acting and double-acting cylinders?
A single-acting cylinder uses air to push in one direction and a spring to return. A double-acting cylinder uses air for both strokes, giving force in both directions.
Which material did you select for the main parts and why?
Mild steel (MS) is used for the frame because it is strong, cheap, easy to cut and weld and available everywhere. Shafts are made of EN8 or bright mild steel for strength, and parts that do not carry load can be aluminium or acrylic to reduce weight.
What factor of safety did you take in your design?
A factor of safety of 2 to 3 is taken for static parts and 3 to 5 for parts under shock or fatigue loading. Allowable stress = yield strength ÷ factor of safety, and each part is checked against it.
How did you estimate the cost of the project?
The cost is the sum of raw material, bought-out parts, machining or fabrication and overheads. Our estimate for this model is about ₹12,700 to ₹18,700, depending on size, material and the workshop rates in your city.
Which manufacturing processes were used?
Cutting and grinding of sections, arc or MIG welding of the frame, drilling for mounting holes, followed by assembly, alignment and painting.
Is your system open-loop or closed-loop?
Mainly open-loop: the controller runs the actuators for a set time or number of steps. Adding a sensor for feedback would make it closed-loop and more accurate.
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Want to build Automatic Knock Detector Pneumatic Door Opener Using Piezo?
Send your college, deadline and team size. We confirm the scope, cost and what you will submit.