This breakout board will solve all your power-monitoring problems. Instead of struggling with two multimeters, you can just use the handy INA219B chip on this breakout to both measure both the high side voltage and DC current draw over I2C with 1% precision.

Most current-measuring devices such as our current panel meter are only good for low side measuring. That means that unless you want to get a battery involved, you have to stick the measurement resistor between the target ground and true ground. This can cause problems with circuits since electronics tend to not like it when the ground references change and move with varying current draw. This chip is much smarter – it can handle high side current measuring, up to +26VDC, even though it is powered with 3 or 5V. It will also report back that high side voltage, which is great for tracking battery life or solar panels.

A precision amplifier measures the voltage across the 0.1 ohm, 1% sense resistor. Since the amplifier maximum input difference is 320mV this means it can measure up to 3.2 Amps. With the internal 12 bit ADC, the resolution at 3.2A range is 0.8mA. With the internal gain set at the minimum of div8, the max current is 400mA and the resolution is 0.1mA. Advanced hackers can remove the 0.1 ohm current sense resistor and replace it with their own to change the range (say a 0.01 ohm to measure up 32 Amps with a resolution of 8mA)

We include a 6-pin header (so you can easily attach this sensor to a breadboard) as well as a 3.5mm terminal plug so you can easily attach and detach your load.

Usage is simple. Power the sensor itself with 3 to 5VDC and connect the two I2C pins up to your microcontroller. Then connect your target power supply to VIN+ and the load to ground to VIN-. We have a detailed tutorial that will do all the gain, range and math for you – just plug and go with Arduino or CircuitPython!

As if that weren’t enough, we’ve now also added SparkFun qwiic compatible STEMMA QT connectors for the I2C bus so you don’t even need to solder the I2C and power lines. Just wire up to your favorite micro using a STEMMA QT adapter cable. The Stemma QT connectors also mean the INA219 can be used with our various associated accessories. QT Cable is not included, but we have a variety in the shop.

Technical Details

Revision History:

• As of January 29, 2021, we’ve updated this sensor to our STEMMA QT standard for sensors. There are now four mounting holes and two STEMMA QT connectors for plug-and-play connectivity! The schematic is the same; only the mechanical shape has changed.

• Datasheet, Fritzing, and EagleCAD PCB files available in the product tutorial
• 0.1 ohm 1% 2W current sense resistor
• Up to +26V target voltage
• Up to 3.2A current measurement, with 0.8mA resolution
• Note: The terminal block included with your product may be blue or black.
• This board/chip uses I2C 7-bit addresses 0x40, 0x41, 0x44, 0x45, selectable with jumpers

Product Dimensions: 25.6mm x 20.4mm x 4.7mm / 1.0″ x 0.8″ x 0.2″

This breakout board solves power-monitoring problems by using the INA219 chip to measure both high side voltage and DC current draw over I2C with 1% precision.

Important Note: Due to chip shortages, updated versions of this board use either INA219A or INA219B chips in SOT-23 or SOIC packages. The INA219A has 1% max current measurement error, and INA219B has 0.5% max current measurement error.

The INA219 allows high side current measuring up to +26VDC, even though powered by 3 or 5V. It measures voltage across a 0.1 ohm, 1% sense resistor with a precision amplifier and uses a 12-bit ADC for current measurement.

The sensor includes a 6-pin header for breadboard connection and a 3.5mm terminal plug for easy attachment/detachment of your load. STEMMA QT connectors make I2C wiring solderless and easy to use with various accessories.

• Measures up to +26V and 3.2A current with 0.8mA resolution
• 1% or 0.5% current measurement error depending on chip version
• Simplifies current and voltage measurements on high side
• Includes 6-pin header, 3.5mm terminal block, and STEMMA QT connectors
• Compatible with Arduino and CircuitPython with available tutorials

Product dimensions: 25.6mm x 20.4mm x 4.7mm / 1.0″ x 0.8″ x 0.2″.