MCU-219 INA219 I2C Interface Zero-Drift Bidirectional Current/Power Monitoring Sensor Module

Description

The MCU-219 is a breakout module built around the Texas Instruments INA219, a zero-drift, bidirectional current and power monitor with an I2C/SMBus-compatible interface. It measures the voltage drop across a shunt resistor and the bus supply voltage simultaneously, calculating current and power internally and reporting all values digitally—no external ADC, op-amp, or reference required .

The INA219 senses bus voltages from 0V to 26V and operates from a single 3V to 5.5V supply, drawing a maximum of 1mA . It features 12-bit ADC resolution, 16 programmable I2C addresses (configurable via the A0/A1 pins), and programmable conversion times and filtering . The B-grade version offers 0.5% maximum accuracy over temperature .

The module is widely used for battery monitoring, solar panel analysis, motor current sensing, and power consumption logging . Most breakout boards include a 0.1Ω shunt resistor for currents up to approximately 3.2A; higher currents require replacing the shunt and recalibrating .

Critical limitations: The INA219 is a high-side current sensor. Low-side sensing is not recommended because it introduces ground lift and can cause I2C communication errors . The maximum shunt voltage range is ±320mV; exceeding this with the default 0.1Ω shunt limits current measurement to ±3.2A . The module is not isolated—the bus voltage and the I2C ground share a common reference, so the measured system and the microcontroller must share a ground.

Features

• Bidirectional Current Sensing: Measures both charge and discharge currents (positive and negative) .

• Voltage, Current, and Power Output: All three values calculated internally and read via I2C .

• Zero-Drift Architecture: Stable measurements over temperature and time .

• Wide Bus Voltage Range (0–26V): Suitable for 5V, 12V, and 24V systems .

• 16 Programmable I2C Addresses: Multiple modules can share one bus via A0/A1 pin configuration .

• Programmable Calibration and Filtering: Adjustable conversion times and averaging for noise rejection .

• 3.3V and 5V Logic Compatible: Works with Arduino, ESP32, and Raspberry Pi .

• Compact Breakout: Standard 0.1″ header spacing for breadboard use.

Technical Specifications