Hi,
I recently stumbled on a nice empty house at the fringes of my city. The homeless people are generally treated like shit under capitalism.
The house had a trapdoor, to a cellar. If it had been closed, maybe with a carpet no urban explorer would find it. Now all stuff I am writing is purely hypothetical, and I don’t intend on doing any of this.
The cellar is pretty empty, It has an empty shelf, where you could store can food, a mattress is very easy to come by, batteries can provide electricity which can be swapped out every week or something like that. So a homeless person could easily live there.
The only real challenge, which could really destroy the whole operation is ventilation. The air is pretty stale, and if the trapdoor is closed I only really see one small window which is blocked by leaves. Leaving this unaddressed could be really fcking dangerous. No questions that CO2 sensors have to be installed, but that is not enough. There needs to be ventilation. But there are 2 constrains:
- it has to be quiet. Urban explorers cant hear a constant humming
- major changes can only really happen in the cellar, and shouldn’t be clearly visible to the outside.
Fortunately I can work with micro-controllers enough to do some stuff. I thought that I run 2 pipes out of the window, roughing them up and covering them with a camouflage net and then leaves (making it look like it belongs seems better but idk how). Then I put two computer fans on it, one sucking one pulling, and they run pretty quickly at the day, when no movement is detected, turn of if movement is detected and don’t run / run very slowly at night.
I have no expertise on ventilation at all, maybe someone can share their ideas and expertise, providing an alternative plan, or improving upon my ideas.
Also for which gasses should I buy sensors? Safety is important, and it is important that no mold forms (no mold formed in 20 years when the trapdoor was open and noone was in there so that’s good.)
CO2 is heavier than O2 and naturally sinks to the bottom. So you’d need to install ventilation pipes around the room, connecting between cellar floor level and the ground level above. A computer fan is not big enough to cut it, and you are thinking about it the wrong way as well. You need to move large volumes of air, so the smaller the fan diameter, the more RPMs you need to achieve desirable movement of sufficient air volume, which means more sound produced by the movement of the fan.
What you could do is take a couple old stand or wall fans and weld them together to create a 6-blade double-sided fan. Then dig an S-tunnel for ventilation, and line it with aluminum or PVC to create a sterile surface. Install the fan somewhere in the middle, and connect it to a fan motor modified to work at slower RPMs for silent running, but running constantly.
You can camouflage the ventilation tunnel’s exit by building a small structure around it that makes it look like a brick grill maybe. Whatever ventilation system you use, you’ll need it to be covered to protect the fan’s electrical system and the cellar itself from rain. You’ll also need to install grills/filters to prevent critters from moving through, especially stuff like mice, snakes, or venomous insects/arachnoids.
As for mould, you need to make sure the place is not susceptible to humidity, so a simple dehumidifier should suffice.
Aside from a CO2 sensor, it wouldn’t be a bad idea to also have a humidity sensor and maybe a carbon monoxide sensor as well. You don’t need much else.
Very great advice, I don’t want to kill people but help them after all. But if I remember correctly the cellar was about 10m². Did you mean combining blades of fans?
Also have you done this already once or more? And if so, can you share pictures?
Yeah combining blades into one.
I have done something similar but not for living conditions. Rather for a room containing fermenters. I don’t have pictures to share though, since I no longer work at that place.
You need a carbon monoxide detector not carbon dioxide. I don’t know if that’s just a mistake but monoxide is the dangerous one that’s more dense than oxygen and puts people to sleep.
I assumed his plan was to have a carbon dioxide sensor that would activate the fan. Humans don’t breathe out carbon monoxide and it doesn’t float in the atmosphere in large quantities, so while life-saving by itself, a CO sensor would be useless for activating the fan regularly. For purposes of ventilation, a rise in carbon dioxide concentration means a reduction in oxygen.
Carbon dioxide is heavier than carbon monoxide by the way.