E&TC / ECE · Embedded and digital electronics · Final year project
Coin Operated Water ATM with Bottle Dispenser
A water ATM that sells drinking water and refillable bottles. Users insert coins to get a measured quantity of water or a bottle, reducing the use of single-use plastic bottles at stations and public places.
What is the Coin Operated Water ATM with Bottle Dispenser project?
A water ATM that sells drinking water and refillable bottles. Users insert coins to get a measured quantity of water or a bottle, reducing the use of single-use plastic bottles at stations and public places.
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
- ₹3,400 – ₹5,100
- Guidance from
- ₹9,999 (Hardware / IoT Final Year)
How the Coin Operated Water ATM with Bottle Dispenser 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 Arduino Uno R3 reads the inputs, runs the decision logic written in C/C++ and drives the outputs.
- The RFID reader with tags reads the unique ID of an RFID card or tag held near it so the system can identify the user or item.
- The Solenoid lock locks or unlocks the door when energised.
- The LEDs indicate status.
Block diagram
Inputs
4×4 matrix keypadController
Arduino Uno R3Communication
RFID reader with tagsOutputs
Solenoid lockLEDsComponents 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 |
| 4×4 matrix keypad | 1 | Lets the user enter a PIN, amount or settings. | ₹90 |
| RFID reader (RC522) with tags | 1 | Reads the unique ID of an RFID card or tag held near it so the system can identify the user or item. | ₹220 |
| Solenoid lock (12 V) | 1 | Locks or unlocks the door when energised. | ₹450 |
| LEDs (assorted) | 1 | Indicate status. | ₹20 |
| 12 V power adapter / step-down transformer | 1 | Supplies stable low-voltage power from the mains. | ₹250 |
| Valves (solenoid / direction control) | 1 | Control the direction and flow of air or fluid. | ₹900 |
| Passive components, PCB and wiring kit | 1 | Resistors (assorted), capacitors (assorted), PCB / breadboard and cables, connectors and jumper wires. | ₹310 |
| 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 | ₹3,400 – ₹5,100 |
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 | ₹3,400 – ₹5,100 |
| 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 Coin Operated Water ATM with Bottle Dispenser project?
A water ATM that sells drinking water and refillable bottles. Users insert coins to get a measured quantity of water or a bottle, reducing the use of single-use plastic bottles at stations and public places.
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 Arduino Uno R3 reads the inputs, runs the decision logic written in C/C++ and drives the outputs. The RFID reader with tags reads the unique ID of an RFID card or tag held near it so the system can identify the user or item.
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 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.
How does RFID work?
The reader produces a 13.56 MHz (or 125 kHz) field that powers the passive tag through induction. The tag replies with its stored unique ID, which the controller compares with its list of authorised IDs.
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.
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 acts locally and sends the data or alert wirelessly. The power supply section feeds every block.
Which communication protocols are used between the modules?
SPI for the RFID reader or radio module. 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?
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.
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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Want to build Coin Operated Water ATM with Bottle Dispenser?
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