How it work?

It is a new knowledge that certain animals specially insect can sense reflected UV light. A dragonfly  and butterfly use UV pattern on wings to identify species and sex. And scorpion glows in UV touch. 

It turns out that mosquito in General can see UV light. They try to avoid UV light as it evidence from the disappearance of them in board day light. With the secret that mosquito hated sunlight because of the UV, one can create a led UV light with simple circuit. 

Led UV light is common in market. It is so mild that a AA battery is able to turn it on. It is used in many nightclub and car flooring. 

Wall socket ----- LED light ---- enough to cover a bedroom. Usually it is placed at one corner. As night fall, the lamp sensed the lack of light and turn the LED on. It will turn off by its in the morning.