I can't understand this circuit board

[Shauryafrom2006]

TL;DR

I am unable to understand this circuit, help would be appreciated.

 

[phinds]

Since you have posted no circuit diagram, just a pic of some components, no one here is going to be able to figure it out either. It's a bunch of components, not a circuit, as far as we can see.

 

[Rive]

Some kind of cheap battery management and some kind of (likely cheap) LED control.
Can't even see the chip markings.
What's written on U1?

 

[Baluncore]

Welcome to PF.

I am unable to understand this circuit, help would be appreciated.

What does it do, is it a motion sensing light, or a fire alarm ?
Why does it have a USB connector ?

The PR 9490 component in the middle of the PCB looks like an infrared detector.
Does it have a multi-facetted lens in the outer case that is not shown ?

 

[Averagesupernova]

https://www.google.com/search?q=yx-...rgBA8gBAPgBAYgGAQ&sclient=mobile-gws-wiz-serp