Green Screen developed for shooting video/photo using camcorder or photo camera with device and green replaced with screen capture.
- Three key colors green, blue and white.
- Brightness control - you can adjust brightness of display for better light balance between ambient light and screen light to prevent glare effect.
If glare is to much with max screen brightness, then try to reduce ambient light, if it not possible then use polarised filter.
Shake device for change settings.
SDK 13
Sleep Sounds: relaxing sounds 
dB meter - noise measure 
Ruler - tape measure length 