How to increase humidity

hey man, you mean like a really micro humidifier? there's a bunch of non-technical ways, if you want a technical design you probably need to hire an engineer or architect lol . in normal conditions i would suggest an evaporative cooler, and in a way you can do that here too , but it's tough. basically you're only real chance is to put a glass or a plate of water (more surface area more evaporation more humidity) in front of your air intake . this should raise it just a few points ... but the best is still to spray the inside walls of the box, this is the same technique as a propagator or for mushrooms, you can get the humidity high enough like that but it's not automatic, so you do have to be on top of things. Hope this helps ! 🚀