Project Hub /Basic Analog & Power Electronics/Power Supplies & Voltage Regulators/STM32 Reverse Osmosis Controller (ROC) Board

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6 – 12 Hours

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STM32 Reverse Osmosis Controller (ROC) Board

A custom industrial 2-layer PCB designed around the STM32G0F6Px microcontroller for automated reverse osmosis system management.

Originally published on Hackaday.io

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
LM2596 Step Down DC-DC Buck Converter Rs. 99.00
2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: STM32 Board
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Solenoid / Electric Lock
Water Pump / Valve
Turbidity / pH / TDS Sensor
Custom PCB / PCB Fab

Browse all components

How It Works

The STM32 Reverse Osmosis Controller (ROC) Board is a custom 2-layer printed circuit board designed to automate a complete reverse osmosis water purification system. At the heart of the system is the STM32G0F6Px microcontroller, which monitors and manages all operational states. The board is powered by a 24V DC main power supply, which is stepped down via an onboard buck converter circuit to supply the proper operating voltage for the low-voltage logic and the microcontroller. The system monitors water conditions and flow safety through several inputs, including a TDS sensor to measure water purity, a low-pressure switch to detect feed water availability, and a high-pressure switch to monitor tank capacity. Based on these sensor readings, the microcontroller triggers low-side MOSFET drivers to control high-power peripheral components safely. These outputs drive the inlet solenoid to start water flow, the flush solenoid to clean the membrane, and the booster pump to maintain adequate pressure across the reverse osmosis system. By sequencing these valves and the pump automatically, the circuit ensures efficient water purification while protecting system hardware from dry running or over-pressurization.

Why Build This

Design and implement a custom 2-layer printed circuit board for real-world industrial or residential water treatment automation.

Integrate low-side MOSFET driver circuits to safely interface low-power microcontroller logic with high-current inductive loads like booster pumps and solenoids.

Program an STM32 microcontroller to process analog sensor data (TDS and pressure switches) for closed-loop appliance control.

Real-World Application

Automated residential or industrial reverse osmosis water purification systems.

Skills You'll Learn

Custom PCB design in KiCad

buck converter power supply layout

low-side MOSFET inductive load switching

microcontroller sensor interfacing

automated fluid control system programming

Safety Precautions

Ensure proper handling of 24V DC power supply and high-pressure water components to prevent electrical shock or water damage.

Technology Tags

STM32

PCB

KICAD

EMBEDDED SYSTEMS

POWER ELECTRONICS

BUCK CONVERTER

MOSFET DRIVERS

SENSORS

WATER TREATMENT

Frequently Asked Questions

Can I power the STM32G0F6Px directly from the 24V DC supply?

No, the 24V DC main power must be stepped down using the onboard buck converter circuit to supply a safe lower voltage to the microcontroller logic.

Why are low-side MOSFET drivers used instead of connecting the pump and solenoids directly to the microcontroller GPIO pins?

Microcontroller GPIO pins cannot supply the high voltage and current required by inductive loads like pumps and solenoids; MOSFET drivers act as electronic switches to handle the heavy power safely.

What software tools do I need to complete this project?

You will need KiCad for designing and modifying the custom PCB layout, and STM32 development tools for writing, compiling, and flashing the control firmware.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

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