Solar Powered RFID Water Vending Machine Using ESP32

Access to clean drinking water is still a challenge in many public places, rural areas, schools, and outdoor environments. In public places, the biggest problem faced by the public is clean water. Traditional water vending systems often require continuous power sources, manual operation, or expensive infrastructure.

For this project, I wanted to explore whether a smart water dispensing system could be built using low-power embedded hardware, RFID authentication, and solar energy. This vending system operates by solar energy.

The result was a Solar Powered RFID Water Vending Machine built around the ESP32 microcontroller.

This project combines:

1. ESP32 embedded system
2. RFID-based user authentication
3. solar power integration
4. automated water dispensing
5. IoT-ready architecture
6. low-power system design

The goal was to create a compact and energy-efficient smart vending solution suitable for real-world public usage.

The hardware setup included:

1. ESP32 development board
2. RFID RC522 module
3. relay module
4. water pump/solenoid valve
5. solar panel
6. rechargeable battery
7. voltage regulation circuitry
8. status LEDs
9. pipes and dispensing setup

The ESP32 acted as the main controller responsible for authentication, dispensing control, and system logic.

The idea behind this project came from a simple problem.

Many water distribution systems still rely on manual operation or require stable electrical infrastructure. In outdoor or remote locations, continuous electricity availability can become a major limitation. We see in many places there is a lack of clean and purified water.

I wanted to build a system that could:

1. operate using solar energy
2. reduce manual operation
3. provide controlled water access
4. support smart authentication
5. work as a low-power embedded solution

RFID authentication was added to make the system more secure and user-friendly while also opening possibilities for prepaid or smart access systems in the future.

The complete workflow is fairly simple.

When a user scans an RFID card near the RFID reader, the ESP32 verifies the card information stored in the firmware.

If authentication is successful:

1. the relay activates
2. the water pump or solenoid valve turns ON
3. water gets dispensed for a fixed duration
4. the system automatically stops after the timer ends

The solar panel continuously charges the battery, allowing the system to operate even in outdoor environments without direct electrical supply.

The system was designed to remain lightweight, low-power, and efficient for long-term operation.

RFID was one of the most important parts of this project.

Instead of relying on manual switches or buttons, RFID cards allow controlled access to the vending system.

Some benefits of RFID integration include:

1. secure user access
2. contactless operation
3. low-cost implementation
4. scalable user management
5. future prepaid integration possibilities

The RC522 RFID module communicated with the ESP32 using SPI communication.

The firmware continuously monitored RFID input and triggered dispensing logic whenever an authorized card was detected.

One of the biggest goals of the project was reducing dependency on traditional power sources.

The solar setup included:

1. solar charging system
2. rechargeable battery backup
3. regulated power output for ESP32 and peripherals

Since the ESP32 is already a low-power microcontroller, it worked well for solar-based operation.

Power optimization became extremely important during development because the system needed to remain stable even under varying battery conditions.

Some optimizations included:

1. efficient relay timing
2. low-power idle states
3. controlled peripheral usage
4. optimized firmware loops

The firmware was developed using embedded C/C++.

The ESP32 handled:

1. RFID card reading
2. authentication logic
3. relay control
4. dispensing timing
5. system monitoring

The firmware logic was intentionally kept modular so additional features like cloud connectivity, mobile monitoring, or usage analytics could be added later.

One major advantage of ESP32 is the built-in WiFi and BLE support, which makes future IoT expansion much easier.

Like most embedded hardware projects, several practical challenges appeared during development.

1. Power Stability

The system needed stable voltage regulation because both the relay and water pump introduced fluctuations during operation.

2. Outdoor Reliability

Since the project was designed for semi-outdoor use, power efficiency and component protection became important.

3. RFID Detection Accuracy

RFID scanning distance and card positioning needed proper testing to ensure reliable authentication.

4. Water Control Timing

The dispensing duration had to remain accurate while avoiding unnecessary water wastage.

5. Solar Charging Optimization

Balancing charging speed, battery backup, and system runtime required multiple iterations.

After multiple rounds of testing, the system successfully handled:

1. RFID-based authentication
2. automatic water dispensing
3. solar-powered operation
4. stable embedded control
5. low-power system behavior

The project demonstrated how embedded systems and IoT-focused hardware can be used to build practical smart vending solutions for real-world environments.

Here is the Dwin HMI display video designed for clarity:

Some future upgrades I may explore include:

1. cloud monitoring dashboard
2. mobile application integration
3. prepaid RFID wallet system
4. remote usage analytics
5. QR-based authentication
6. battery health monitoring
7. IoT-based maintenance alerts

The system can also be adapted for:

1. smart water ATMs
2. public utility vending
3. industrial fluid dispensing
4. automated refill stations

This project was a great learning experience in embedded systems, power management, RFID integration, and smart automation design.

What started as a simple vending concept eventually became a complete embedded hardware system involving firmware development, solar power optimization, authentication logic, and real-world automation challenges.

Projects like this show how ESP32 and low-power IoT hardware can help build practical and scalable smart infrastructure solutions.

I mainly work on embedded systems, IoT product development, firmware engineering, and custom hardware solutions using ESP32, RFID, BLE, and connected embedded devices.

If you want to read the full project you can visit this link: https://digitalmonk.biz/solar-powered-rfid-water-vending-machine-esp32/

This project is great, well experienced and iot related.As a leading Embedded Software Development Company, we develop reliable firmware and intelligent embedded solutions for IoT, automation, and connected devices.

We develop more vending machines and we add features like cashless payment, human friendly, lightweight and display system. We design and develop custom vending machine with smart features and automatic work.