CJMCU-219 INA219 I2C Interface Zero Drift Bi-directional Current / Power Supply Monitoring Module

The CJMCU-219 INA219 Module is a compact, high-precision current, voltage, and power monitoring module designed for measuring electrical parameters in DC-powered systems. Based on the Texas Instruments INA219 current/power monitor, it provides accurate measurements while communicating with a microcontroller through the I²C interface.

The module is suitable for Arduino, ESP32, Raspberry Pi, STM32, and other compatible microcontrollers, making it a convenient solution for battery monitoring, power-supply testing, robotics, IoT devices, and embedded energy-management projects.

High-Precision Current and Power Monitoring

The INA219 measures the voltage across an external shunt resistor to determine the current flowing through a load. It can then combine the current measurement with bus-voltage information to calculate the system’s power consumption.

This allows the module to monitor:

• Bus voltage
• Shunt voltage
• Load current
• Power consumption

The 12-bit ADC provides detailed measurement resolution, while the INA219’s zero-drift architecture helps maintain stable measurements across operating conditions.

Bidirectional Current Sensing

The CJMCU-219 supports bidirectional current measurement, allowing it to monitor current flowing in either direction.

This makes it useful for applications such as:

• Battery charging and discharging
• Bidirectional DC power systems
• Energy storage projects
• Motor and actuator monitoring
• Power supply testing

The direction and magnitude of current can be processed by the connected microcontroller for monitoring, logging, or control purposes.

I²C Communication

The module uses the I²C communication interface, allowing it to communicate with a wide range of development boards using only the SDA and SCL lines.

It can be integrated into projects based on:

• Arduino
• ESP32
• Raspberry Pi
• STM32
• Other I²C-compatible microcontrollers

The module’s I²C interface supports high-speed communication according to the capabilities of the INA219 and the host system.

Wide Bus Voltage Measurement

The module can measure DC bus voltages from approximately 0V to 26V, making it suitable for monitoring many low-voltage power systems.

Typical applications include:

• Battery packs
• DC power supplies
• Embedded systems
• Motors and actuators
• IoT devices
• Robotics platforms

Always ensure that the voltage applied to the module remains within the specified operating limits.

Zero-Drift Architecture

The INA219 uses a zero-drift measurement architecture designed to reduce measurement errors caused by temperature and long-term drift.

This makes the module suitable for applications where stable and repeatable current measurements are important.

The actual accuracy of the complete module depends on factors such as the shunt resistor, PCB layout, temperature, wiring, calibration, and operating conditions.

12-Bit Resolution

The INA219 provides 12-bit ADC resolution for bus-voltage and shunt-voltage measurements. This allows the connected controller to obtain detailed electrical measurements for monitoring and data logging.

The module can therefore be used in projects where basic current sensing is not sufficient and more detailed power information is required.

Compact Design

The CJMCU-219 has a compact design that makes it suitable for embedded applications and space-constrained projects.

The included 2-pin terminal block provides a convenient connection point for the measured power path, while the 6-pin connector can be used for power, I²C, and related connections according to the module’s pin configuration.

Easy Microcontroller Integration

The module can be easily incorporated into software-controlled monitoring systems. A microcontroller can periodically read voltage and current measurements over I²C and calculate or display power consumption.

This makes the CJMCU-219 useful for:

• Real-time monitoring
• Data logging
• Battery analysis
• Energy consumption tracking
• Power optimization
• Fault detection

Key Features

• Based on Texas Instruments INA219
• Measures voltage, current, and power
• Bidirectional current sensing
• 12-bit ADC resolution
• Zero-drift architecture
• I²C communication interface
• Bus voltage measurement up to 26V
• Low offset voltage
• Compact module design
• Suitable for Arduino, ESP32, Raspberry Pi, and STM32
• Useful for battery and energy monitoring
• Includes terminal block and connector

Specifications

Specification	Details
Product Name	CJMCU-219 INA219 Monitoring Module
Main IC	INA219
Measurement	Voltage, Current & Power
Bus Voltage Range	0–26V
ADC Resolution	12-bit
Current Sensing	Bidirectional
Interface	I²C
Architecture	Zero-Drift
Maximum Error	Approx. 1%*
Offset	Approx. 100 µV*
Applications	Power & Energy Monitoring
Connector	2-Pin Terminal + 6-Pin Connector

*Actual accuracy depends on the shunt resistor, board design, temperature, calibration, wiring, and operating conditions.

Applications

The CJMCU-219 INA219 module is suitable for:

• Battery monitoring
• Battery charging and discharging analysis
• Power supply monitoring
• Energy metering
• DC load monitoring
• IoT power management
• Robotics
• DC motor monitoring
• Embedded systems
• Portable electronics
• Smart devices
• Power optimization projects
• Electronic testing and experimentation

Battery Monitoring

The bidirectional sensing capability makes the module useful for monitoring rechargeable battery systems.

A controller can monitor the current flowing into or out of a battery and combine this information with voltage measurements to determine the instantaneous electrical power.

With suitable software, users can also record charging and discharging data for further analysis.

Robotics and Motor Monitoring

The module can be incorporated into robotics projects to monitor the power consumed by motors, actuators, or other DC loads.

Current monitoring can help developers identify:

• Increased mechanical load
• Excessive current consumption
• Motor operating conditions
• Battery usage
• Abnormal system behavior

For motor applications, appropriate filtering and wiring should be used to minimize the effects of electrical noise.

Arduino and ESP32 Compatibility

The I²C interface makes the module convenient to connect to Arduino and ESP32 development boards.

A typical connection uses:

• VCC → compatible supply
• GND → common ground
• SDA → I²C SDA
• SCL → I²C SCL

When connecting the module to a 3.3V controller, verify the I²C pull-up voltage and logic-level compatibility before powering the system.

Package Includes

• 1 × CJMCU-219 INA219 I²C Current/Power Monitoring Module
• 1 × 2-Pin Terminal Block
• 1 × 6-Pin Connector

Important Notes

• The module is designed for DC voltage and current monitoring within its specified limits.
• Do not exceed the 26V bus-voltage rating.
• Actual maximum current depends on the shunt resistor and specific module configuration.
• Measurement accuracy depends on the shunt resistor, temperature, PCB layout, wiring, and calibration.
• Ensure correct polarity and wiring when connecting the measured load.
• Check I²C voltage levels before connecting the module to 3.3V microcontrollers.
• For high-current applications, use appropriately rated wires, connectors, terminals, and protection components.
• Product images and PCB layouts may vary slightly between production batches.

Why Choose the CJMCU-219 INA219 Module?

The CJMCU-219 INA219 I²C Current, Voltage & Power Monitoring Module offers a convenient way to add accurate electrical monitoring to embedded projects. Its 12-bit resolution, zero-drift architecture, bidirectional current sensing, 26V bus-voltage capability, and I²C communication make it a practical choice for battery management, robotics, IoT, energy monitoring, and power-supply testing.

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