This was inside the bill of a baseball cap with the word "MARINES" on the front. I tried changing the batteries, but it doesn't seem to be doing anything. Does anyone know what this is?
It has a button on one side. But new batteries didn't reveal it's purpose. I'm thinking it's too corroded now to work. I know that round thing is a simple speaker or buzzer, but I don't know (a) what sound it's intended to make and (b) why it was sewn into the bill of a baseball cap.
Internals, image 1:
Internals, image 2:
External, backside:
Cap pictures:
Edit: added images of the internals.
Edit 2: added a small description of the button, and why I didn't just test it with new batteries (I did, but it doesn't work). So, basically, all I know.
Edit 3: added a picture of the backside of the casing.
Edit 4: Adding pictures of the cap itself.
Thank you, everyone, for all of your input. If I'm ever able to get this thing working, I'll add a video of the device and it's audio.
There is no microchip which means it can't be a listening/recording device. Seeing as the circuit is very simple, my bets would be on it being some kind of oscillator, as I can't see what else you could build using only two components. An oscillator circuit produces a single unchanging, constant tone. I know that circuits making high pitched tones are used to repel moles (in gardens) and teenagers (in shopping centers). I guess they could be used to repel, like, moths as well?
Edit: didn't notice the blank epoxy blob. Yeah that's a microchip