Sensors fo measuring power through 110-220V lines

I’m looking for a sensor I can connect to Arduino that will measure the power through a higher voltage line (110 or 220V) and return results in such a way that I can read them on an Arduino (either though Analog, I2c, serial, etc…).

I’ve not gotten far with google, as the keywords intersect with many irrelevant results (low power sensors, or results on the power consomption of sensors, etc…)

Technically you could set something up on your own through voltage division. All you would need is a few high power resistors to hook up to the analog input. The analog input does have a 5V limit, and I am pretty sure the input is limited to a DC resolution, but I can’t remember 100%. You would need to limit the current going into the analog ports to around 40mA (so selecting the right resistors is important).

Now if you are wondering if there is some sort of Arduino daughter board, I am not quite sure of a product that does that.

When you say measure power are you looking to verify that the power is on or are you looking to see if you have 110 vs 220 voltage?

Or by Power are you looking to measure Power used(Voltagexcurrent) at a specific voltage?

Depending on the questions I think we could narrow down better options. For instance if you are looking to measure power we have several options in current sensor including some boards that would be easily intigrated into an Arduino. You would need to know the amount of current that could be going though the line to make sure the sensor can handle that range.

Hi Robert,
Those are great suggestions
I’m trying to measure actual power (in W) or energy (in J or kWh… can integrate power or differentiate energy to go back and forth)
For a home application (AC 220V)

Thought about measuring current and multiplying by 220 to get power but that wouldn’t adapt automatically to 110V system I have Elsewhere.

Which is why I’m wondering whether there’s a component that measures power ( or energy over time) but more as a standalone sensor independent of voltage as a parameter.

A current sensor could be a interesting option, at least for the moment. One of your suggestions that caught my attention were the ACS723 boards ( But can those measure current through a 220V line (such as, for example, a lamp at home powered by the main electrical lines) ?

There is no single sensor, at least as far as I’m aware, that provides an output measured in Watts or Joules. You will need to combine a current sensor of some kind and a method to determine your line voltage.

As for your other question, a current sensor like ACS723 uses the Hall effect to measure current using magnetic fields and is galvanically isolated from the rest of the circuit. The sensor’s isolation is rated for a working voltage of 297V (rms) so it would be fine for 220V line voltage. Sparkfun notes that their breakout board for the ACS723 isn’t designed to handle the IC’s maximum isolation of 2.4kV, but they don’t say what their actual max is. I would assume it’s okay for 220V though.

In general, a current sensor doesn’t care about voltage because that’s not what you’re putting into the device.