I did a thing I used the Zooz Multi Relay's input from the dry contact to detect if the dryer was running. There are a lot of wires in my house from the previous owner being an alarm installer so I found one that used to go to a window and went to where the alarm panel is. I have my Zooz where that panel is.
I put one wire on the dryer's circuit through this thing:
and when the dryer is running it powers a relay and closes the relay. You can set the sensitivity of when it closes the relay with a screw. So it powers on when the dryer is running then you can make it close if the heating element is on or just if it senses any power. It is fully self powered off of the magnetic field of the power going through it.
I connected the 2 wires coming off that to the Zooz and now it "turns on" one of the inputs on the Zooz when the dryer is on. So on the dashboard the switch associated with that input shows on when it is running. All that thing does is close the relay when it senses enough power to trip your threshold but it powers up when power is flowing through it.
One thing that is strange and it could be how my dryer works but the motor that spins the clothes doesn't seem to pull power down the leg that I have this thing on. It only shows the dryer is on when the heating element is running. I haven't taken the time to try to put the other hot leg through the hole because this works just fine for me.
Thinking this could be used for people with fireplace fans or furnace fans or other things too that you want something to happen if said device is on. Other people on Amazon have commented using it to close the relay and trigger something based on their AV receiver turning on. You could even take apart a contact sensor and hook it to this thing instead of the reed switch. It is a dry contact thing it just closes a relay to complete a circuit the same as the reed switch would do.