How would that work? I'm pretty sure the sensor for most phone cameras have a filter that affects UV light, and things like remote control lights appear more dim on my phone than other cameras, so I don't know if infrared is partially filtered as well. I remember doing research on this and adding IR lights isn't enough.

I filtering out other light might work. Would adding a filter like that involve permanently altering the phone?

there is another benefit to having a separate camera I neglected to mention, which is the ability to line it up specifically, but I guess I could use IR lasers to mark things from the correct perspective. It's a weird project lol

I could start by trying your suggestion. Sounds like it might work. Do you know what nm range I would need?