N.E.R.D. – Watermaker Controller

Smart embedded control for marine watermakers

N.E.R.D. = Nautical Embedded Resource Director

An embedded control system for marine watermakers, based on ESP32 architecture with touchscreen UI and modular RS485 communication.

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What this project does

The N.E.R.D. Watermaker Controller provides real-time control and monitoring of a marine reverse osmosis system.

It allows you to:

• Control feed pump and high-pressure pump
• Manage flushing cycles
• Switch between tank and test modes
• Monitor flow, pressure and TDS in real time
• Track pump runtime (persistent)
• Adjust system parameters via touchscreen

The system is designed for reliability, simplicity and transparency.

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System Architecture

The system is built using two microcontrollers:

ESP32-S3 (Main Controller)

• 4.3" touchscreen display (800x480)
• LVGL 8.4 user interface
• Full system logic
• RS485 Modbus Master
• Sensor processing
• UI management

ESP32-C3 (Remote Module)

• Modbus RTU Slave
• Flow pulse counting
• Analog input expansion (TDS, pressure)
• Relay control interface

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Communication

• Protocol: Modbus RTU
• Bus: RS485
• ESP32-S3 = Master
• ESP32-C3 = Slave

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User Interface

Main Screen

• Pressure gauge (BAR / PSI)
• Flow gauge (L/h / GPH)
• TDS gauge (PPM)
• System status
• Control buttons:
  • Feed Pump
  • H.P. Pump
  • Flush
  • Mode (Tank / Test)

Settings Screen

• H.P. pump runtime
• Flush preset
• Flow fine tuning
• Sensor configuration

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Screenshots

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Hardware

Typical setup:

• ESP32-S3 4.3" Touch Display
• ESP32-C3 module (RS485)
• I2C FRAM module (for persistent runtime and system data storage)
• RS485 relay board (Modbus)
• MAX3485 TTL to RS485 interface module
• RS485 analog acquisition module (for pressure and TDS)
• Flow sensor (pulse output)
• Pressure sensor (0–5V | 0-100 BAR)
• TDS sensor (Arduino TDS Meter V 1.0)

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Firmware Structure

firmware/
  S3_Controller/
  C3_Module/

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Requirements

Software

• Arduino IDE
• ESP32 board package by Espressif (Arduino core)

Libraries

• LVGL 8.4.x (REQUIRED)
• ESP32_Display_Panel
• ESP32_IO_Expander
• esp-lib-utils

⚠️ This project is NOT compatible with LVGL 9.

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Features

• Stable LVGL UI (no blocking)
• Round-robin sensor polling
• Optimized Modbus communication
• Persistent runtime storage
• Modular architecture

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Project Status

Version: v1.0.0

• Stable
• Long-run tested
• No critical crashes
• Ready for real-world usage

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Design Philosophy

• Non-proprietary components
• Industrial reliability
• Cost efficiency
• Full transparency

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License

This project is released for non-commercial use only.

See LICENSE file for details.

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🌊 N.E.R.D. Ecosystem

This project is part of:

N.E.R.D. – Nautical Embedded Resource Director

A modular embedded system platform for marine applications.

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Contributing

Contributions and improvements are welcome.

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Note

Built by nerd sailors, for nerd sailors.