Smart Fertigation System ODM Case Study: RK3568-Based Intelligent Fertigation Control Board

1. Project Overview

As precision agriculture continues to develop, automated fertigation systems are becoming increasingly important for greenhouse cultivation, commercial farming, and modern irrigation management.

Unlike conventional irrigation controllers, a smart fertigation system needs to manage multiple processes simultaneously, including water supply, fertilizer mixing, nutrient concentration monitoring, dosing control, and irrigation scheduling.

The customer planned to develop an integrated smart fertigation machine that combines water supply management, fertilizer dosing, EC/pH monitoring, irrigation control, and remote management in one system.

To meet these requirements, a customized embedded control platform was designed around an RK3568-based mainboard, combined with an independent MCU for real-time equipment control.

The solution provides a Linux-based interface for configuration and data management, while dedicated control hardware handles sensor acquisition and multi-channel actuator operation.

2. Final Product Definition

Product Name: Smart Fertigation System Control Terminal

Application: Precision Agriculture, Greenhouse Automation, Agricultural Irrigation, and Automated Fertilizer Management.

The system is designed to provide centralized control of water and fertilizer delivery while maintaining accurate monitoring of critical operating parameters.

Key Functional Requirements

The modular design allows the system to support different irrigation configurations, fertilizer combinations, and equipment requirements.

3. Hardware Architecture

The proposed hardware architecture uses an RK3568 embedded computing platform as the main application processor, together with an independent MCU for real-time control tasks.

3.1 RK3568 Mainboard

The RK3568 platform serves as the central computing unit, responsible for:

• Running the embedded Linux operating system.
• Managing the local HMI and configuration interface.
• Executing fertilizer recipe management software.
• Storing operating parameters and historical records.
• Handling network connectivity and remote communication.
• Coordinating application-level commands with the independent controller.

The Linux platform provides the processing and software flexibility required for an intelligent agricultural control terminal.

3.2 Sensor Acquisition Interfaces

The system integrates multiple sensors to monitor water quality and equipment operating conditions.

Typical monitoring inputs include:

• EC sensors for electrical conductivity measurement.
• pH sensors for acidity and alkalinity monitoring.
• Flow sensors for water and fertilizer delivery measurement.
• Pressure sensors for pipeline pressure monitoring.
• Liquid-level sensors for tank status detection.

Depending on the selected sensor models, the acquisition circuits can use dedicated analog front ends, ADC interfaces, RS485 communication, and electrical isolation.

3.3 Independent MCU Control

An independent MCU handles time-sensitive control tasks, including:

• Multi-channel dosing pump control.
• Water pump switching.
• Solenoid valve operation.
• Mixing motor control.
• Sensor sampling and local interlock logic.
• Equipment status feedback.

This architecture separates application-level processing from real-time equipment control, improving system responsiveness and making the control logic easier to maintain.

3.4 Power and Output Driver Circuits

The control board requires dedicated driver circuits for pumps, solenoid valves, and other electrical loads.

Depending on the equipment specifications, the hardware may incorporate:

• Isolated digital input and output circuits.
• Relay or MOSFET driver stages.
• Motor and pump control interfaces.
• Overcurrent and reverse-polarity protection.
• Power supply filtering and grounding design.

The final circuit configuration depends on the rated voltage, current, load characteristics, and safety requirements of the connected equipment.

4. Key ODM Development Challenges

Developing a smart fertigation controller involves more than integrating a processor and several sensor interfaces. Measurement accuracy, dosing consistency, electrical reliability, and control coordination are all critical to the final product.

Challenge 1: EC/pH Sensor Analog Front-End Design and Calibration

EC and pH sensors have different electrical characteristics and measurement requirements.

In particular, pH electrodes typically have high output impedance and are sensitive to electrical interference. EC measurements also require appropriate excitation and signal conditioning based on the selected probe technology.

Using a generic ADC circuit without considering sensor characteristics may result in measurement noise, signal drift, or unstable readings.

The ODM development process therefore needs to consider:

• Sensor-specific analog front-end circuit selection.
• High-input-impedance signal conditioning for pH measurement.
• ADC resolution and measurement accuracy.
• Input protection and electrical isolation.
• Temperature compensation requirements.
• Sensor calibration procedures and parameter storage.

Another important consideration is interference from pumps, solenoid valves, and mixing motors.

The hardware design should evaluate whether actuator switching introduces noise through the power supply or ground paths. Appropriate PCB layout, grounding, filtering, and isolation strategies help improve measurement stability.

Challenge 2: Multi-Channel Fertilizer Dosing and Flow Control

A fertigation system may need to control multiple fertilizer tanks, dosing pumps, water pumps, and irrigation valves.

Different pumps and dosing mechanisms may have different flow characteristics. Therefore, the control system needs to coordinate pump operation with sensor feedback and target fertilizer recipes.

Key development considerations include:

• Independent control of multiple dosing channels.
• Configurable dosing parameters.
• Flow measurement and cumulative volume calculation.
• Pump operating sequence and timing control.
• Calibration of dosing volume under agreed operating conditions.
• Abnormal flow and equipment fault detection.

The software and hardware interfaces should be designed together to ensure that each output channel corresponds correctly to its assigned actuator.

Challenge 3: Real-Time Control and Linux Application Coordination

The RK3568 Linux platform provides a flexible environment for application development, local interaction, and network communication.

However, time-sensitive pump and valve operations should not depend entirely on high-level Linux application scheduling.

Using an independent MCU allows the system to execute real-time control logic while the RK3568 handles user interaction, recipe management, data storage, and remote communication.

The communication protocol between the two processors should define:

• Command formats and parameter ranges.
• Equipment status feedback.
• Communication timeouts.
• Error codes and fault reporting.
• Recovery and synchronization mechanisms.

This separation improves software modularity and makes future feature expansion easier.

Challenge 4: Equipment Safety and Abnormal Condition Handling

Agricultural equipment may operate for extended periods without continuous human supervision.

The system should therefore support fault detection and appropriate interlock strategies.

Typical conditions include:

• Low liquid level in fertilizer tanks.
• Insufficient water supply.
• Abnormal pipeline pressure.
• Unexpected flow readings.
• Sensor disconnection or measurement errors.
• Pump or valve control failures.
• Communication interruptions.

The controller can execute predefined responses, such as stopping the affected dosing channel, suspending irrigation, generating an alarm, or switching to a safe operating state.

The exact response strategy should be determined by the equipment design and application-specific safety requirements.

5. Software Architecture and System Functions

The software architecture is divided into the Linux application layer and the independent real-time control layer.

5.1 Local HMI and Recipe Management

The local interface provides operators with access to system configuration and operating information.

Main functions include:

• Real-time sensor value display.
• Fertilizer recipe creation and editing.
• Irrigation schedule configuration.
• Pump and valve operating status.
• Manual operation and maintenance controls.
• Alarm history and event records.
• Sensor calibration and parameter configuration.

Operators can save multiple fertilizer recipes and select the appropriate configuration according to different crops, growth stages, or irrigation requirements.

5.2 Data Logging and Remote Management

The Linux system can maintain historical records of important operating parameters and equipment events.

Typical recorded data includes:

• EC and pH measurements.
• Water and fertilizer consumption.
• Pump and valve operating status.
• Irrigation start and stop times.
• Recipe execution history.
• Sensor calibration records.
• System alarms and fault events.

With network connectivity, the system can also support remote status monitoring and configuration through an agreed communication architecture.

Modbus can be integrated for communication with external industrial controllers, PLCs, and compatible monitoring systems.

6. System Verification and Acceptance Testing

To ensure that the fertigation controller meets its intended application requirements, the development process should include hardware, software, sensor, and integrated system testing.

Additional validation can cover communication stability, power supply performance, environmental operating conditions, and recovery after unexpected interruptions.

Specific acceptance values should be defined according to the selected sensors, pumps, system configuration, and customer requirements.

7. KICKPI Embedded Linux ODM Development Capabilities

A smart fertigation controller requires coordinated development across embedded computing, sensor interfaces, industrial control, and application software.

KICKPI provides customized embedded hardware and software development services for agricultural automation and industrial IoT applications.

Our engineering capabilities can support:

• RK3568-based embedded computing platform integration.
• Custom motherboard and peripheral interface design.
• Sensor acquisition and communication interface development.
• MCU-based real-time control integration.
• Multi-channel pump and valve driver circuit design.
• Embedded Linux system customization.
• Local HMI and application software development.
• Communication protocol integration.
• Prototype testing and production preparation.

From hardware architecture planning to software integration and prototype validation, KICKPI can work with customers to develop embedded control platforms tailored to their equipment requirements.

Looking for a Custom Fertigation Controller or Agricultural Automation Board?

Contact KICKPI to discuss your project requirements, including sensor interfaces, dosing channels, communication protocols, operating environment, and production targets.

Our engineering team can help evaluate the hardware architecture and develop a suitable embedded Linux ODM solution.

Website: https://www.kickpi.com/

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