Moonlight
About
Moonlight is an app that could help you with your sleep apnea or upper airway resistance syndrome.
It works by offering a gentle vibration or chime anytime you roll towards your back.
Further Reading
For more information on why this is relevant, please see this blog post
To learn more about the interactions of sleep position, heart rate, and oxygen saturation, check out this post.
Android
Currently available for free on the Google Play Store
iOS
If there is interest in an iphone version, please let me know at: support@moonlightapp.zendesk.com