Arrival sensing

I am fairly new to SmartThings and home automation in general, but learning quickly. (I’ve figured out how to install and use webCoRE, that counts for something, right?)

Currently I am using my Android phone as an arrival sensor to accomplish some automation tasks, but I would like the zone to be smaller, and triggering actions using GPS location on an android phone has not been all that reliable for me. So I have several questions…

1.) Is there a way to use my phone as an arrival sensor NOT with GPS location, but simply by sensing whether it’s within range of the hub? To do this, would I simply turn off the “location aware” feature in my routines that use my phone?

2.) I know that the official SmartThings arrival sensor could work, but the idea of adding a bulky fob to my keychain that does nothing other than say “I’m here” to the hub doesn’t excite me. So, what about other devices, such as this keyfob, which is about the same size but also has buttons on it? Would this be seen by SmartThings as an arrival sensor AND buttons that I could use to perform other tasks?
http://www.zigbee.org/zigbee-products-2/#zigbeecertifiedproducts/productdetails3/55792a5b22ca411079bc2fcf/

3.) On the same vein as question 2, will anything listed on that Zigbee HA products page work with SmartThings?

Thank you Robin, I’ve read that post 3 times already but the answers to the questions I posted above were not clear to me from reading that.

The article linked above is a good reference. You can group the options into Geolocation some kind of network presense (wifi/zibee/etc).

I’ve written a piston to use a combination of two of them. Network presence and geolocation using the smartthings app. Basically if both network and geolocation are not present then consider me away and if either are present then consider me present.

The latest update they released for iOS has been solid on my phones and has not given me any issues. They spent a bit of time on it and I was ready to send them a report from the app anytime it failed. It has not failed yet.

Also keep in mind, network type presence requires that you be within range of the devices for it to kick in. So for Wifi you want to make sure the signal is strong enough that it picks it up in time before you unlock the door if you have a security system. I found with my iPhones when they were locked they actually drop off the network and connect back every few minutes. So the network presence is setup to only mark it as away if its offline for more than 5 minutes or so.

The SmartThings presence sensor is actually pretty small. About the size of my car’s key fob.