I need to make a flush iron trap door

I need to make a trap door that, when provided input, opens up. However, the redstone must be entirely underground. It is okay if the redstone is visible from within the hole, I just need it to not be exposed to the surface.

Make it work like in the image, but I don't want to be able to see the redstone from my viewing angle.

As you want it to open upwards, the trapdoor must be 1 block above floor level. This gives 6 possible blocks to power the trapdoor from:

However, 5 of these possible blocks would be visible to the surface, meaning that on a flat floor the only choice remaining is to power the trapdoor from directly below.

I'd recommend doing so by using a redstone torch like this:

Which, without the glass, can be hidden to the surface: