Review on S12SD 200-370nm UV Detection Sensor Module Light Sensor for Arduino - Optimize Your Search! by Daniel Shankle

So far it works as tested on all fake UV LED crap on the net. Very easy to set up. I used a USB cable, cut off the end and used it to power the board. I ran 2 short jumper wires from the board so I can connect the DVM. If it is a true UV LED it will get 5 volts DC in output or signal. Once you have 5 volts DC, place a mug or piece of glass between the source and this circuit board. If the voltage drops sharply then you have a legitimate UV-C source as glass or plastic will block it. Quartz will happen.