What could this PCB be for?

Question

I am not sure PCB identification is on-topic for this site, please let me know if it isn't.
My wife found this PCB in her bag. She thought I had given it to her, but I do not recall that at all. Does anyone know what it could be from or for?

It is around 31 by 37 mm in size. On on side it has four pushbuttons and a small blue led, which blinks at different frequencies when different buttons are pushed. On the side it has what looks like a micro-USB connector.
On the other side it has two small IC's, one with 14 legs and H3-100 written on it, the other has ATMLH434, 16CM Y, 4W2601B, and a search brings up some shopping sites with little information, but there are IC's with the same first line that seem to be eeprom chips.
The PCB itself says 215BHS-1.
Does anyone have any idea what this could be? Thanks!

David Norman · Answer

it looks like one of those RF key fobs to switch on a remote relay or something. The LED turns on when any of the buttons are pressed and the RF on the other side of the board sends the signal out. This is a Transmitter only. I think the long IC is the USB to TTL logic converter and the small 8 pin IC could be a microcontroller or as Dave mentioned, could be EEPROM, but for EEPROM to function correctly, it needs a microcontroller so my best guess would be that is a micro processor, like ATTINY variant or TST microelectronics.

Answered by David Norman on January 10, 2021

Dave Tweed · Answer

Note the relatively heavy trace along the right side of the second image, and the fact that there's no ground plane on the other side in that area. That's an antenna. Note also several spiral coils elsewhere on both sides of the board.
This is an RF remote control of some sort.
The 8-pin chip may well be a serial EEPROM of some sort. The larger chip is probably a custom ASIC, although there's some chance that it might be a relatively general-purpose MCU with RF hardware built-in.

What could this PCB be for?

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