Do I need a smartphone to use Billy? Steph P July 29, 2019 04:14 Updated Yes, the Billy kit works with the Billy app on your smartphone. Billy will work on any iPhone running iOS 9.0 or above, or any Android phone with Android 5.1 or above. Related articles Do I need the internet to use Billy? Will Billy know if I have a fall? How do the multi-purpose sensors work? Can I buy more sensors?