Suppose we have a bunch of Lego-like bricks that can be attached together to make a temporary or permanent dwelling space. They might include LEDs for lighting, 240VAC outlets, speakers, mattresses, cabinets, drawers, carpets, mirrors, ovens, stove burners, air conditioners, refrigerators, toilets, etc. If the size and connectors are standardized, they can be composed in a variety of different Minetestish ways to make temporary or permanent furniture or dwelling spaces, perhaps inside of an existing suboptimal dwelling space.
You could imagine locking together a few dozen such independently wheelable blocks into a modular “dwelling machine” or “habitaculum” inside an arbitrary apartment, perhaps occupying some 10 m² of floor space and containing bed, desk, and shower, standing off the floor on short legs.
(I read a book from the 01970s recently that mentions in passing that the author’s friends did something like this in their shitty apartment in La Boca in Buenos Aires. I think it might have been Hennessey and Papanek’s Nomadic Furniture 2 or Papanek’s Design in the Real World.)
Some of the deficiencies of existing dwelling spaces that can be thus remedied:
Inadequate air conditioning. Here in Argentina many windows have roll-down shutters above them which permit wind to blow right through, and the regulations require 100 cm² openings in the walls where gas appliances are installed to prevent gas buildup. The resulting quantity of airflow on a hot windy day makes adequate air conditioning very difficult to achieve. A small, relatively sealed inner space without gas appliances can be free of such unwanted air leaks and can be air conditioned much more cheaply.
Air filtering. The covid pandemic has made us aware that our indoor air is generally of very poor quality, and that this is a major risk not only for contagion of respiratory diseases like covid, but also for health in general. One of the biggest problems, especially in big cities like Buenos Aires with lots of high-sulfur diesel, is particulate pollution; pollen and mold spores are problems for sensitive people even in other places. Again, this is a difficult problem to solve without being able to limit the ingress of bad air, but an easy one to solve with controlled airflow.
Thermal insulation, which makes air conditioning much more reasonable. Most buildings here are made of concrete with single-paned windows. The 10 m² habitáculo suggested above might have 45 m² of surface area (25 m² of walls and 20 m² of ceiling and floor). If this is all sheathed with 100 mm of 0.3 W/m/K insulating material, maintaining a 20° difference through the wall (e.g., from 21° within to 41° without, or 21° within to 1° without) requires 2700 W of heating or cooling power; with a typical CoP of 3, this is an air conditioner of only 900 W. Thicker insulation than this may be feasible, cutting the required power further, and usually the temperature delta is much smaller.
Storage. Many apartments and houses do not have much storage built in, being designed for consumers or socialites rather than craftspeople or the self-sufficient.
Flooding. I just found a roll of toilet paper that had been water-damaged under the sink today; I guess the pipes are leaking again. I’ve had my clothes, neatly stacked in the closet, turn moldy from water leakage from a poorly constructed bathroom. When it rains, the roof here has leaked in two different rooms, creating big puddles on the floor before the landlord fixed the roof. In the apartment where I lived in La Boca, there was such a big hole in the roof that there were mushrooms growing down from the ceiling. Sometimes there’s widespread flooding when rains outpace the storm sewers, although here in Buenos Aires the last big floods were about 10 years ago before they fixed the storm sewers. Most commonly only a centimeter or two of water gets onto your floor, but that’s enough to ruin your computer, short out your power strip, ruin your mattress (if it’s on the floor), destroy your tatami, and demolish your books (if they’re on the floor). All of this can be avoided if everything is up off the normal floor, especially if the habitaculum itself is watertight.
Lighting. Most buildings are inadequately lit (50-500 lux), which possibly causes seasonal affective disorder, widespread depression, and sleep phase disorders. Full daylight is 10-25 kilolux in the shade, about 100 times brighter, and direct sunlight is 100 kilolux. A lux is a lumen per square meter; to illuminate a black room to 1 kilolux requires a kilolumen per square meter, while a white or mirrored room may be about five times as efficient. For our example 10 m² habitaculum with 45 m² surface area, if we paint it white, we might need 9 kilolumens per kilolux. Both Samsung and Philips are shipping 200-lumen-per-watt LEDs since 02017, ordinary fluorescent tubes can hit 100 lm/W, ordinary LED bulbs are in the neighborhood of 75 lm/W, and sunlight is 93 lm/W. So reaching 10 kilolux might require 90 kilolumens and thus 450-1200 watts powering the lights, or less in a smaller area, and about US$20 worth of fluorescent tubes or US$500 worth of LEDs.
Mosquitoes. In the Boca apartment with mushrooms growing from the ceiling, we constantly had mosquitoes because, as with most Argentine houses, there were no screens on the windows. (For a while I dated a woman who had moved into an apartment in terrible condition with screens on all the windows. As part of her renovation, she removed the screens because she didn’t like how they looked.) Excluding mosquitoes from a small space without windows is easier than excluding them from a large space with windows.
Spaces totally without amenities. There are numerous industrial and storage spaces, both in Argentina and in the rest of the world, that have electrical power, or can get it, but lack running water, climate control, floors, sewage treatment, and so on. These spaces are often much cheaper to rent than more livable spaces in the same area. An easily portable modular habitaculum could provide a convenient alternative to a camping trailer.
Noise. If you have many centimeters of some kind of sound-absorbing material between you and the outside world, you will be less annoyed by the superchargers on buses interrupting your conversation.
Portability. Moving out is a huge pain in the ass. This was a major motivation for Papanek’s Nomadic Furniture and _Nomadic Furniture 2.
Coziness. A small space can be much more comfortable than a large one if properly organized.
Saving wear and tear on the property. When you move out, it’s nice if you don’t have to repaint.
Standard residence doors range from 625 mm up to maybe 900 mm in width, and from 2000 mm on up in height. Standard residence ceilings are about 2.6 m high, though occasionally there are small areas with lower ceilings; you need at least 2 m of height inside the habitaculum for most people to stand up comfortably, and probably more like 2.2 m. The oppressive feeling of such a low ceiling can be relieved by covering most of it in mirrors, doubling the visual height of the space to 4.4 m.
For individual modules to fit through a standard door under the power of a single person, they ought to have wheels built into them or trivially attachable, be no wider than 500 mm (to permit passing through a 620-mm doorway at up to a 36° angle), be no taller than 2000 mm (they can be tilted over to go through low doors), and be no longer than 1000 mm in order to be manageable in size for a single person. This ½ × 2 × 1 m size is roughly that of a stack of three single-bed-sized mattresses, or half of two Minetest blocks. To be comfortably pivotable on a corner, they ought to weigh no more than 80 kg, so you never have to lift more than 40 kg; a weight of 40-60 kg, or even less, would be much better.
This presumes that the modules should have the shape of a rectangular paralellepiped. While aesthetically and in terms of structural strength this might leave something to be desired, walls are traditionally vertical so as to be in a local gravitational stable equilibrium, and floors, beds, counters, and tables are necessarily horizontal. So polyhedra of higher degrees of symmetry like the Platonic dodecahedron, or of lower numbers of connection points like the tetrahedron, would seem to be impractical.
If your wall modules are exactly 2 m tall, your ceiling or floor module will need to have some extra space to get up to 2.2 m inside space; 2.0 m is rather cramped.
So a minimal construction set for a 3.5 m × 3.5 m space (12.25 m²) might consist of 16 outer wall modules (0.5 m × 2 m × 1 m), 4 ceiling corner modules (0.25 m × 2 m × 1 m), 4 non-corner ceiling modules (same), and another 8 floor modules, 32 modules in all, occupying some 24 m³ in storage and enclosing 3.5 m × 3.5 m × 2.2 m = 26.95 m³. Some of the modules might contain Murphy beds, others closet space, others air conditioners.
The minimal volume to merely enclose that space would of course be much smaller, consisting of thin cubicle-like panels (or panels similar to Symons forms), perhaps only 20 mm thick. That would reduce the total volume when disassembled to something like 0.64 m³.
The modules could connect together at the corners with twistlock-like connectors, modified to permit watertight connections between them, or with wedge connectors like the “wedge bolts” that connect concrete-form panels. Probably the walls will not have to withstand more than 2 kN of force, which probably will not have more than a 4:1 mechanical advantage against the corner connectors (spread across two corners), so with 250 MPa A36 mild steel connectors you only need about 16 mm² of tensile cross-section per connector to keep the modules together. So it ought to be easy enough to use snap connectors like those used in seatbelts. However, connectors should not protrude from the surfaces when not in use (that would make the modules uncomfortable to sit on or lean against), and because you might want to disconnect a module that’s currently connected to two or more other modules, it needs to be possible to disengage the connections while the modules are still in contact; turning a knob should enable you to engage or disengage them. (Knobs are less likely to be actuated unintentionally than buttons, levers, and the like.)
The modules could probably be built as welded angle iron frames, plus panels to give them rigidity. Each wall module has 14 meters of edges (4 × (½ + 1 + 2)). Metals Depot will sell you hot rolled A36 12mm × 12mm × 3mm angle iron for US$5/m, and they say it weighs 570 g/m, so this would work out to 7.9 kg and US$70, which is a lot less than 80 kg but a bit pricey. 18-gauge A513 12mm × 12mm square tube is a little lighter but costs more than twice as much. They also sell ASTM A527 18-gauge (1.3 mm) galvanized steel sheet for US$73/m², saying it weighs 10.5 kg/m², which is a slightly lower price per kg.
On Mercado Libre, Almacen Techista here in Buenos Aires sells 30-gauge (“C30”) galvanized (0.3 mm) for AR$2100 for a 1×2 m sheet, weighing 5.05 kg. At today’s quote of AR$194.50/US$ that’s US$10.80, US$5.40/m², or US$2.14/kg, a dramatically lower per-kg price than Metals Depot. They also sell 18-gauge cold-rolled (1.25 mm) for AR$6050 for 1×2 m, which would be about 20 kg, US$31, and US$1.58/kg, which is cheaper than the galvanized (at Metals Depot cold-rolled is dearer than hot-rolled, which is dearer than galvanized).
Also on Mercado Libre, Gramabi sells 20 mm × 20 mm × 1.25 mm square steel structural tubing for AR$1600 for 6 m, US$8.22, US$1.37/m. I think that’s 1.19 kg, so US$6.90/kg, which is more similar to the Metals Depot prices. But this might be a better grade of steel than the galvanized roofing sheet metal.
Some of these modules include things that can be controlled or monitored electronically without a lot of bandwidth, such as LEDs, fluorescent lights, air conditioners, heat exchangers, speakers, or thermometers. If each face of a module where it can be latched onto another module has an electronic connector as well, and the microcontroller in each module can identify its module type, distinguish between the different connectors, and detect their orientation, then they can build a constantly updated model in memory of the whole assemblage of modules and all of their hardware, permitting it to be controlled and monitored from a larger computer.
It’s maybe not necessary for the modules to have electronic (and electrical power) connectors on every surface. Legos only have mechanical connectors on two of their surfaces, only four connectors in the simplest general case; tee connectors have only three ports and are capable of being assembled into two- and three-dimensional networks. (Think of a cube that can couple to other cubes on three of its faces.)
This idea seems really cool: you could snap together some modules into a custom ad-hoc dwelling machine that is immediately reflected in the mirror world inside your laptop, from which you can control it.
Interestingly, although I had forgotten this, Nomadic Furniture 2 profiles a system of modular cubes called “Palaset” by Ristomatti Ratia, which is in some ways very similar. They’re polystyrene cubes designed for storage (shelving, drawers, cabinets) that you can also sit on, with a 13½” outside size and ¼” walls (345 mm and 6 mm), linked together with doublestick tape and by inserting asterisk-shaped plastic “dowels” into holes on their faces. Some of these are evidently still available 49 years later at palaset.com for about 20 euros each, though perhaps not as many as were profiled in the book.
The ClicBot educational robot kit works more or less the way I describe above, with sensors and connectors to create a VR model of the physical robot that you can then program, but it’s for building tabletop robots, not dwelling-machines.