Is your dryer purely Electric or Gas+Electric ?
In the latter case, how about using a smart plug with energy monitoring, such as the TP-Link KP115? I believe OpenHab has a binding for TP-Link already. By monitoring the energy consumption, you can tell whether the dryer is running or done.
Now, there are ongoing discussions in other threads as to whether those plugs (they are rated for 15 Amps) are suitable for reactive loads (coils in the dryer, due to the motor). Some say they only work with resistive loads (cos phi = 0), but many use them for fans and many other/different applications.
The other option is to bypass Sense completely and snap a CT sensor in your power panel, cook up a low cost current sensor with Arduino, and you have a direct reading of the energy drawn by the dryer. Of course, you have to set some thresholds as I’m guessing the dryer won’t be the only device in that circuit.
Also, and depending on how old the dryer is (mine is 12), some have a buzzer at the end of the dry cycle. If you’re feeling brave you can open up the dryer’s back and connect something there that sends notifications … but that’s getting a bit complicated already.
The reason I mentioned all these options is that often, to have a reliable system, you should aim for a direct measurement of whatever quantity you’re after. Sense works in the cloud, sometimes is sluggish/unresponsive, then you have one/multiple software layers (Openhab and other dependencies … ) You get my drift. The more complicated the chain, the less reliable it is.
Thoughts ?