I would say try Brillo, Android for Internet of Things devices announced by Google in May 2015. Brillo will also work with Wi-Fi and Bluetooth LE,if you are a developer, otherwise get something off the shelf that works. I have experience with ZigBee and it can be a pain at times, but could be made to work over a yard that is less than an acre it is low power and can be used with repeaters.
