E&TC / ECE · Embedded and digital electronics · Final year project
Automatic Liquid Dispenser Vending Machine
A coin-operated liquid soap vending machine. A coin acceptor registers payment, the user chooses a quantity, and a pump dispenses it while a load cell under the container measures the exact amount delivered.
What is the Automatic Liquid Dispenser Vending Machine project?
A coin-operated liquid soap vending machine. A coin acceptor registers payment, the user chooses a quantity, and a pump dispenses it while a load cell under the container measures the exact amount delivered.
Key facts
- Branch
- Electronics & Telecommunication (E&TC / ECE); also suits Mechatronics, 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
- ₹3,000 – ₹4,400
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Automatic Liquid Dispenser Vending Machine works
- 12 V power adapter / step-down transformer supplies the circuit; a regulator gives the controller and sensors a steady 5 V.
- The Load cell with HX711 amplifier measures weight.
- 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 Mini submersible water pump moves water for irrigation, dispensing or cooling.
- The 16×2 LCD with I2C adapter shows readings, status and messages to the user.
- The LEDs indicate status.
Block diagram
Inputs
Load cell with HX711 amplifierPush buttons and switchesController
Arduino Uno R3Outputs
Mini submersible water pump16×2 LCD with I2C adapterLEDsComponents 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 |
| Load cell with HX711 amplifier | 1 | Measures weight. | ₹350 |
| Push buttons and switches | 2 | Provide manual inputs and the power switch. | ₹80 |
| Mini submersible water pump (12 V) | 1 | Moves water for irrigation, dispensing or cooling. | ₹180 |
| 16×2 LCD with I2C adapter | 1 | Shows readings, status and messages to the user. | ₹220 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| 12 V power adapter / step-down transformer | 1 | Supplies stable low-voltage power from the mains. | ₹250 |
| Coin module | 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 | ₹3,000 – ₹4,400 |
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 | ₹3,000 – ₹4,400 |
| 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 Automatic Liquid Dispenser Vending Machine project?
A coin-operated liquid soap vending machine. A coin acceptor registers payment, the user chooses a quantity, and a pump dispenses it while a load cell under the container measures the exact amount delivered.
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 Load cell with HX711 amplifier measures weight. 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 a load cell measure weight?
Strain gauges bonded to the metal beam change resistance as it bends. They form a Wheatstone bridge whose tiny output is amplified and digitised by the 24-bit HX711.
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.
How is the pump switched by the controller?
Through a relay or MOSFET, because the pump runs at 12 V and draws more current than the controller pin can provide.
Why is an I2C adapter used with the LCD?
It reduces the wiring from about 10 pins to 2 (SDA and SCL), leaving more controller pins free for sensors.
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?
I2C for the display, RTC or motion sensor (only SDA and SCL lines) 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.
Is your system open-loop or closed-loop?
Closed-loop: sensors measure the actual position, distance or condition and the controller corrects the actuators until the target is reached.
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.
Related projects
Academic use: Project Buddyy offers mentoring, guidance and reference material for learning. You stay responsible for following your institution's academic integrity rules and for understanding everything you submit.
Want to build Automatic Liquid Dispenser Vending Machine?
Send your college, deadline and team size. We confirm the scope, cost and what you will submit.