I am making a device that needs to send me a notification/text/email to my phone when another device is turned on or off. This device does not have a signal output or anything so I am thinking I would somehow tap into the 120V AC wire and connect it somehow to something like an ESP32 or ESP8266 and when it would detect a current flowing through the wire, it would send a message to my phone.
Does anyone have any ideas for something that could tap into the 120V wire, keep the circuit going (maybe like a relay) and let my ESP know if it is on or off?
submitted by /u/ONE_BIG_LOAD
Original article: Looking for something to take 120v as a signal