Place the iPhone near the banana so that the skin fills the preview screen. It does not need to be in focus. Ripeness is displayed numerically as a value between one and ten.
Color blindness is believed to effect 8% of men and about 0.8% of women with Northern European ancestry. Many live normal lives and are only occasionally reminded of their condition.
Buying and eating bananas, something many color blind people avoid, can now be done independently with the use of the Bananarometer.
It works best at distinguishing green from yellow bananas before black spots start to appear.
If you are color blind you can now buy, eat and ripen bananas with confidence.