We have successfully used the device for non-destructive testing of fruit ripeness. Ultra-Violet (UV) fluorescence from Chlorophyll present in the skin of three different kinds of apples - Red Delicious, McIntosh and Empire was measured over the period of 11 days. The data collected showed strong correlation with the ripeness measured by a penetrometer.
There are lot of interesting applications for such a portable device. Imagine carrying such a portable device when you next visit a supermarket, that helps you buy perfectly ripped fruits. Our work is published in Scientific Reports and you can read it in detail here.
Illustration of the device checking for fruit ripeness.