When I wrote the power measurement doc, I was trying to keep it as simple as possible to do the connections. The only parts of the sensor's board I am using is the I2C level shifters, and the easy to plug into connectors. You need to get the 1.8V I2C signals on the Low speed connector up to 3.3 or 5V levels so that they can work with the INA219 board. You can use a discrete level shifter board and some Arduino Jumper wires to achieve the same thing. There are lots of level shifter break-outs available, there is just one example https://www.adafruit.com/products/757
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