IR remote

I'm opened IR remote and found this. Can some one explain me what this black dot in the center of the board for? And how it work, I'd like to do somthing like this using arduino.
Every button contact sends different IR code, I have tested with arduino IR receiver.
Images below

(mod edit)

It’s a blob of resin over a bare silicon die.

The duplicate of the original post has been deleted

Why did you post exactly the same question twice 7 minutes apart ?

Sorry I tried to delete one post but didnt find a button, only modify.

UKHeliBob:
The duplicate of the original post has been deleted

Why did you post exactly the same question twice 7 minutes apart ?

Thanks, but that is controling signal code (how IR light are blinking)?

TheMemberFormerlyKnownAsAWOL:
It's a blob of resin over a bare silicon die.

lpx:
Sorry I tried to delete one post but didnt find a button, only modify.

You need to use the "Report to moderator" link and ask for it to be deleted

It's a microcontroller (likely with program stored in ROM, ie, not reprogrammable) or IR remote controller IC - you'll never be able to find a part number for it (and even if you could, the datasheet would be in chinese)

Those are ubiquitous in low-cost and mass-produced electronics - to reduce costs, instead of using a normal IC, they put the bare silicon chip onto the PCB (sometimes called"wafer scale package", "die scale package", or"chip scale package" and similar in manufacturer documentation) and put a blob of epoxy over it.