Power Outage detector

[asuz]

How can I monitor presence of the electricity at my wall socket? There is no need to monitoring voltage or current just presence of the electricity ? I already have ups or backup energy for if need sensing and reporting devices like internet connection. Should I use a relay or contactor that always plug to wall socket and report 1 state then if the electricity off it reports 0? Just need a safe way. Need advice.

[ThomasB]

There is no need to monitoring voltage or current just presence of the electricity? {snip} Just need a safe way.

One safe way is to power the ESP device without UPS or backup battery. Have it send periodic heartbeat message using timer rule. When power is lost the heartbeat message stops and this condition can trigger your host controller to report/log/do-something/etc.

- Thomas

[xury]

You can use a optocupler connected to gpio.