Straight Back

This App adds a small icon on the top of the device, a sad icon means you should straighten your back to a more ergonomic posture, a happy icon indicates that the device is in a good angle.
Using a better posture may help relieve neck, back and chest pains.
The measurements are taken only when the screen is ON (and after a pre-set period of time), vibration can be added in order to remind the user to change their posture.