Good afternoon everyone, what I try to do is the following, I am trying to use this sensor so that it is sensing the current that passes through one of the power lines of my house and that when there is a power cut the arduino let me know and launch another signal to activate a relay or several relays, I hope you can help me with this, thanks to all. Greetings.

I'm wondering if the purpose of your work is to learn about ACS712 or learn about Arduino or just to monitor and respond to a power fail event. If the latter, then there's no need to implement a micro-controller or indeed ACS712 as there are simpler ways to detect power fail events and trigger a relay via an external circuit and supply.

You solution will need to be powered outside of mains (or it will fail when needed most) and for the great majority of time it will be waiting for a job to do. I guess you could run it on rechargeables maintained while the mains is on, but it does seem wasteful. However, if this is a learning exercise you could have a look through: Using the ACS712 Hall Effect Current Sensor Module (part 1) - YouTube but be warned that experience, knowledge and competence around mains is your own responsibility.

I agree with Steve. It's fraught with danger for a beginner messing with mains electricity.

However, that said, as an excercise.....

That's a current sensor, if no current drawn what then?

No, better to use Steves suggestion to use a mains powered changeover relay in your circuit and when power cut, use the contacts to do whatever you want.

I'm assuming a seperate DC(?) supply for the other relay(s) you mention.

I can understand your need to be notified but how? Email, text or whatever.

Each needs a hardware method. If power cut do you lose internet when the router shuts off for instance, so no wifi or email.
To text requires a mobile connection and SIM module.

Semaphore signalling requires a man with flags....with all the attendant beer and food problems :slight_smile:

Thank you for your comments, I will take into account what you mention, thanks again and greetings partners.