Uhh, because of the heat of the raspberry pi & camera behind there

Suppose you were in this situation and suspected something. I’d imagine the space behind it would be totally dark, so what would be a safe way to check if there’s a gap in between without breaking the glass?

I read a long time ago that putting something flat against the mirror will show you. I think if the mirror is legit you’ll see the reflection directly on the surface, if it’s two way the reflection will look like it’s inside the glass.

But I’ve never had the chance to actually test that, so take it with a grain of salt.

You want there to appear a “space” between your fingertip and the mirror, if touching it directly. If there’s no space, then say cheese.

Surely you could just put another sheet of clear glass on your one-way to avoid this though? Wouldn’t want someone to accidentally scratch the coating and reveal the whole thing anyway