Just installed a dog door and I'd love to know when the dog comes and goes. I have a SmartThings system but their "presence" sensors basically tell if the fob is within range of the mesh network so it wouldn't trigger unless he got out of the yard.
As you can tell by where I'm posting this, I'm still very new at electronics and with so many ways to skin cats, narrowing things down to a handful of sensible ones would be nice.
I don't think I want to use a PIR type sensor or a motion sensor in general on the inside and outside, would trigger when we were near the door as well as the dog just lounging, not necessarily going in/out. Also, I'd love to do a single sensor inside and not double the sensors (one in, one out) or have to worry about weather.
I've looked at some flex sensors. I think two of those would be able to tell me when the dog door flap flexed out or in, but then some questions come up:
1. Flex sensors increase resistance when flexed. Would this be suitable for a SUPER low power zigbee or zwave sensor setup or would they require constant current to detect the change. I'd like it to trigger like a door open/close sensor does... as the event is happening... not a periodic "heartbeat" type sensor read.
2. Could I repurpose an open/close sensor but still be able to read two states (open-out, open-in) when they typically only trigger on open or close. I'm guessing not... so I might end up doing my own Xbee Pro type thing and create a custom device type in SmartThings that can handle three states (open-out, open-in, closed)
I've also thought about capacitive touch sensors (I assume require constant current though).
Ideally, the sensor would require zero power when not in use and only send a signal when it was touched/flexed/etc. I guess there'd need to be a way to trigger "closed" and zero power again though.
I'd love to hear different ways this could be accomplished (not just the possibly objective "best way") as I'm learning and would be curious of the ins and outs of different mechanisms.
Thanks in advance! Hopefully this isn't below even the "Beginner" category.
-Trevor