E&TC / ECE · Security and safety system · Final year project
Configurable Password Security System
A keypad door lock whose password can be changed by the authorised user. An 8051 microcontroller stores the password in EEPROM, checks each entry and drives a motor to lock or unlock the door.
What is the Configurable Password Security System project?
A keypad door lock whose password can be changed by the authorised user. An 8051 microcontroller stores the password in EEPROM, checks each entry and drives a motor to lock or unlock the door.
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
- ₹2,300 – ₹3,400
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Configurable Password Security System works
- 12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V.
- The 4×4 matrix keypad lets the user enter a PIN, amount or settings.
- The Push buttons and switches provide manual inputs and the power switch.
- The 8051 microcontroller with board runs the embedded C program that scans inputs and controls the outputs through its four I/O ports.
- The LEDs indicate status.
Block diagram
Inputs
4×4 matrix keypadPush buttons and switchesController
8051 microcontroller with boardOutputs
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 |
|---|---|---|---|
| 8051 (AT89S52) microcontroller with board | 1 | Runs the embedded C program that scans inputs and controls the outputs through its four I/O ports. | ₹300 |
| 4×4 matrix keypad | 1 | Lets the user enter a PIN, amount or settings. | ₹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 |
| EEPROM | 1 | Part from the design specification | ₹150* |
| Mini Door | 1 | Part from the design specification | ₹150* |
| 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 – ₹3,400 |
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 | ₹2,300 – ₹3,400 |
| 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 Configurable Password Security System project?
A keypad door lock whose password can be changed by the authorised user. An 8051 microcontroller stores the password in EEPROM, checks each entry and drives a motor to lock or unlock the door.
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 4×4 matrix keypad lets the user enter a PIN, amount or settings. The Push buttons and switches provide manual inputs and the power switch. The 8051 microcontroller with board runs the embedded C program that scans inputs and controls the outputs through its four I/O ports.
What is the architecture of the 8051 microcontroller?
The 8051 is an 8-bit Harvard-architecture microcontroller with 4 KB ROM (8 KB in AT89S52), 128 bytes RAM, four 8-bit I/O ports, two 16-bit timers, a UART and five interrupt sources.
How does the controller read a matrix keypad?
It drives one row LOW at a time and reads the columns. A key press connects a row to a column, so the row-column pair identifies the key with only 8 pins for 16 keys.
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 8051 microcontroller with 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.
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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