I have lived in tropical coastal areas and noticed quite large changes
in local humidity but no particular change in local temperature.
These images depict how the photonic sensor translates finger movements into color changes, as the photonic crystal reacts to the change in
local humidity caused by the approach of the finger without direct contact.
There were three silica gels kept inside the box which are used as a desiccant to
control local humidity to avoid spoilage.
They are backed by inexorable logic: for every 1 °C rise in temperature, the potential saturation levels of the air rise by 7 %, so where there is water to be evaporated,
local humidity rises with the thermometer.
«These photonic nanostructures change color in response to variations
in local humidity.
The more complex wet bulb version factors in
local humidity, which affects the capacity of the skin to evaporate moisture and cool the body.