As it turns out, this still wasn’t enough extra distance to fix the parallax problem…I’d need to raise the board just a few more millimeters above the brim.
Your hat/eye/distance situation might be altogether different, so don’t feel like you need to do all this. If your eye reflections are looking good where they are, you can skip ahead to the next section below.
IMPORTANT: I’ve accumulated decades of craft detritus and never throw anything out. While building or adjusting your own hat, I’m not suggesting you should run out and buy any of this stuff! Rummage through your own life’s detritus and see what might work.
I discovered one can’t just raise the board and keep the same eye holes, reason being that the Pepper’s ghost illusion works in three dimensions…it would be like looking down a tube slightly off-axis, partly blocking the screens. So I cut the eye holes a bit bigger.
Also cut a hole so I could run a wire from the battery inside the hat to the board outside, and for a USB cable.
To raise the board a few millimeters, I cut some little blocks out of an old neoprene mouse pad and fixed them in place with hot glue. Foam-core board or corrugated cardboard could also be used.
Make sure the screens align with the holes before the glue sets. If I were doing this over, you’d see a stencil around the screens blocking stray light. This was my prototype and I’d painted over things instead.
Once the board was securely in place, I used the same 3D-printed doodad…but only for holding the screen glass, not the circuit board. Make sure the clip is straight before the glue sets.
Once in place, then I painted over the edge of the clip and anything else shiny in the vicinity to prevent reflections. This is just me being super-persnickety and probably isn’t necessary.
So now there’s this board out in the open on top of the brim.
One option is just to keep it there like that, if it’s less about the costume and more about being able to share the project and show how it works.
I wanted to make some effort to cover the board…and by chance in my craft hoard was some black felt that was an excellent match for the hat. I covered just the front part, held in place with some fabric glue and clamped in place to dry.
Afterward, I trimmed along the edge and also glued on some craft-detritus elastic as a more tasteful replacement for the original hat band.
This does cover up many of the connectors and buttons on the board, so keep that in mind when planning. I need occasional access to the reset button to get the board in bootloader mode for uploading new code, but the fabric has enough “give” that the button can be pressed through it.
It’s a bit lumpy but not super conspicuous. If you really wanted to go all-out one could make an entire fake brim and conceal the board in there.
I’m okay with some stuff showing though, if one goes looking for it. It’s an opportunity to “pull back the curtain” for interested people and explain how it works. It’s also easier to access the power switch this way.
Slip the glass back into place, power it up, and there it is!
Spend a little time practicing with a mirror, cell phone camera or with a friend’s help, learning the best placement of the hat and how much you can turn your head with the illusion intact. I intentionally glued the glass-holding doodad in such a way that it lightly touches my forehead. With some practice, I should be able to sense if the hat is aimed correctly on my head.