UV sensor has maximum sensitivity at a wavelength of 365nm.
It has an effective range of 280nm to 400 nm (thus detecting both
UVA and UVB). UV Index Meter will report a UV Index from 0-16, with
a resolution of 0.1 and an accuracy of 0.5.
UV sensor has a cosine response, within the acceptance angle of + & - 65°
To mount the UV sensor
The plastic dome window I used was the lid off a box containing dog treats. I tested the plastic before I used it, the UV dropped slightly I compensated for this by using the offset in weather display. To fix the clear plastic dome onto the lid I use some araldite around the edge, when this was dry I then used some silicon sealant on the inside to form a good waterproof seal, when everything was dry I filled the inside of the lid with water to see if there were any leaks. I got a small plastic tube to a length that would put the circuit board into the top of the dome. I used some araldite to stick the plastic tube to the bottom of the box, near the top of the tube I drilled a hole straight through this is to feed a cable tie to secure the circuit board on top of the plastic tube. I mounted 4 stainless steel legs which are adjustable to get the box level. In the bottom of the box there are four small breathing holes this is to stop any condensation building up. If the seal did leak around the plastic dome this would not cause any problem as the circuit board is mounted in the middle which acts like an umberella.