Can I use a car keyless fob as a presence device? I’m guessing not but just wondered if they are comparable.
Unfortunately, your guess is correct: you cannot.
The SmartThings branded arrival sensor works in a very specific way. Every 30 seconds it sends a check in message to the hub. And that’s literally all it does. It doesn’t worry about whether it gets a response. It sends the message whether it’s at home or 1000 miles away. It never changes how often the message is sent. Just every 30 seconds “device 47 checking in.”
Everything else is done on the SmartThings side. Your account keeps track of how long it has been since the arrival sensor was last heard from. After three missed check-in, it marks the device as “away.” Then the next time it does receive the check in message, your account marks the device as present. And that’s all there is to it.
It’s a really simple protocol, designed to limit the battery drain on the sensor and the amount of work for the account has to do to keep track of it.
But it can only work with devices that send that specific type of check in message with that kind of regularity using a messaging protocol that SmartThings hears and understands.
Thanks very much for your detailed reply. I did doubt it but wondered. Going to have some more questions but I’ll do a search first…