UV Detector for Measuring Sun Light UV Level - Portable Handheld Sun Light UV Detector (Model 3B)

Without any instructions I can see it's detecting something in sunlight. Seems to suggest my tint is blocking 100% of UV. Deducting a star bc there's no way to turn it off. I left the battery cover off so I can pull the battery when I'm done to turn it off

I wanted something that would give me an idea of exposure time for contact printing with sunlight. This seems to do that ok. There are lots of timer settings that I guess could be used if you wanted to monitor your exposure to the sun - if you can figure out the really, really confusing and obscure instructions.By the way... YOU CAN'T TURN THE SUCKER OFF!!!

I used it to test my car's window tint and it reports 0% and overall it does report but it's very insensitive to minor UV levels. Comparing it with a more high end UV scanner and the UV scanner reports 18% UV transparency while this sensor claims 0.This part is my fault, this scanner fell from my waist and the batteries fell out. Sadly it doesn't turn on anymore. Beware of how fragile it can be.

Bought this, and it always reads 0. Seems like a simple enough device, but I have to believe that the sun would create a reading…

It does seem to measure UV in some way, because simply putting a piece of window glass (e.g. car window, or any other "normal" glass) will drop the UV index reading from ~9 to ~3, which makes sense because regular soda-lime glass blocks UVB but not UVA (note that UVA isn't really so bad for your skin). It is also a good indication because it is not significantly influenced by visible light (400-700 nm). Sunglasses bring the UV index down to almost zero too.But what surprised me is that a (not so powerful) 395 nm UV flashlight (very narrow spectrum LED light source) which is slightly visible to the human eye makes the UV index meter indicate "over range". If it's so very sensitive to light right at the edge of visible light, I suspect it doesn't actually indicate very well how strong the damaging wavelengths of UV light are, since the ozone layer can be thicker or thinner depending on the day and season. Ozone blocks the damaging UV light very well, and is most transparent to around 400 nm. This is why I think that the sensor doesn't give such useful information.Without having access to the specifications on the sensor that is actually used, I can't say that this gives any meaningful information.