Humidity sensor relative to another

I was wondering if someone could help me with a notification I am working on. I have given up on every other type of sensor to notify me when my dryer is done. I stuck a humidity/temp sensor to the inside of my dryer (surprisingly the temps are not above 73 on the door, or i melted the temp sensor portion, lol). I than created a virtual switch and I would like a rule to turn on and off based on the dryers humidity relative to another humidity sensor that I have. I believe this should give me an accurate idea of when my cloths are dry. This feels extremely accurate in my mind because it will tell me how dry my cloths are compare to the air humidity that day.

Second thought (maybe it exists) is a wishlist idea. If Hubitat could make a virtual notification device that allows the user to enter whatever text they want when a condition is met. This device would cover all notifications generated in Hubitat and would fire off once the condition is met and cleared only when the user acknowledges it. So my mailbox, dryer, washing machine, etc all notify to this one device, which can than be displayed on the dashboard and/or texted, announced by a speaker, have a color bulb flashing, etc.

Thoughts on this? Is this more of a dashboard idea and keep the texting/speaker announcment seperate?

That's called a variable. That said if you want it easy, get an iotawatt. Put one clamp on your dryer circuit and one on your washer circuit. Boom instant notification trigger.

You really are trying to get at the essence of "dry" by measuring humidity. Maybe if you hacked any number of the cheap humidity sensors out there and "remote-d" the actual component sensing the humidity (which might cause a reading/power issue) you could wing something. I'm thinking putting such a sensor right at the exhaust end of your dryer vent.

Thinking about this further....there is probably a temperature/humidity relationship which would allow you to use a purpose built (and more reliable temperature probe) in the vented exhaust to "infer" when your clothes are dry. I'd experiment with this relationship to see if it holds before rigging up kit to HE.