# Using INA219 breakout board to measure host arduino's supply voltage and current

Two questions,

Is it possible to use the INA219 breakout board to measure host arduino's supply voltage and current draw without some form of short?

If it can, what would the wiring look like for the 2 input sense wires?

Read the data sheet for the INA219. It is designed to be used with a shunt resistance. Not a short but a low resistance shunt resistance. Using the breakout board makes things a little easier, here is an Adafruit Tutorial on how things are setup.

Ron

Ron_Blain:
Read the data sheet for the INA219. It is designed to be used with a shunt resistance. Not a short but a low resistance shunt resistance. Using the breakout board makes things a little easier, here is an Adafruit Tutorial on how things are setup.

Ron

I've already seen those pages, but they don't answer my specific question.

Most INA219/229 breakout boards come with a build-in 0.1 ohm shunt.
That value enables bi-directional current measurements of up to 3.2Amp.
The INA219 must be used high-side (in the + line), and that can be 0-26volt.

"without some form of short?"
We get current by measuring the tiny volt drop across an almost short.
Leo..

Can it measure current less a shunt? Then no it can't if that is what you are asking. It measures current based on voltage drop across a shunt resistance. With the shunt resistance known the voltage drop will be proportional to the actual current. There is no short unless we choose to call 0.1 Ohm a short. I am assuming you have a breakout board?

Ron

Wawa:
Most INA219/229 breakout boards come with a build-in 0.1 ohm shunt.
That value enables bi-directional current measurements of up to 3.2Amp.
The INA219 must be used high-side (in the + line), and that can be 0-26volt.

"without some form of short?"
We get current by measuring the tiny volt drop across an almost short.
Leo..

The worry about the short was because the device will be measuring it's own power source and I was worried there would be some sort of high power loop that might have fed through the logic side of the arduino/INA219

Anyway my wireless Weather and Environmental Station is nicely recording it's power supply's own voltage levels now and sending that along with other data.