Seen these?
http://microbit.org/about/
Low cost ($A23) device with two user buttons, LED matrix, accelorometer, Compass and BLE!
More expensive than the RPi Zero W, but you can program with Python or block programming for the less talented (like me!!).
Originally intended for the education market, my mind's running wild with ideas (maybe this is the device for those automated sprinkler valves I've been dreaming of?/)