How to Build a Walking Building

Hi! I am an architecture student fascinated by how buildings use energy. For the Make it Spin challenge, I asked myself a radical question: What if the act of cooking could power the kitchen itself?

This project is the Crawler, a nomadic Kebab kitchen designed for the Joshua Tree desert. Instead of using gas or electricity to move, it acts as a thermodynamic machine. The heat generated from grilling kebabs is harvested to spin a central crankshaft. This rotation drives a series of Jansen Linkages, converting the warmth of the hearth into a rhythmic walking gait.

In this Instructable, I will show you how I designed and built a working prototype of this "metabolic architecture"—a structure where food becomes fuel, heat becomes spin, and movement becomes regeneration.

Software:

1. AutoCAD / Revit: For designing the linkage geometry and creating architectural drawings.
2. Fusion: For 3D modeling the crankshaft, simulating the rotation, and preparing files for 3D printing.

Materials:

1. Bristol Paper / Cardstock: For the lightweight chassis.
2. Wooden Dowels (1/4"): Used as the central driveshaft and joint pins.
3. PLA Filament: For 3D printing the linkage arms and joints.
4. Rubber Bands: For tension and grip.
5. High-Grit Sandpaper: To smooth the printed joints.
6. Lubricant (WD-40/ptfe): To reduce friction in the spinning joints.

The concept began with the Kebab. In traditional cooking, a massive amount of heat is lost to the atmosphere. I wanted to capture that "waste" energy.

The Crawler is designed around a Heat Engine principle (similar to a Stirling Engine).

1. The Source: The central grill produces heat.
2. The Spin: This thermal energy creates pressure differentials that spin a central flywheel/crankshaft.
3. The Walk: That simple rotation is fed into the leg mechanism (similar to a Strandbeest).

By linking the kitchen's function (cooking) to its mobility (walking), the building becomes an organic system: it only moves when it is being used.

Designing a mechanism that spins without jamming requires extreme precision. I used AutoCAD and Fusion to engineer the drive train before manufacturing:

1. Geometric Constraints: In AutoCAD, I plotted the 11 specific rod lengths required for the linkage.
2. Rotational Simulation: I moved the design into Fusion to create a Motion Link. By digitally spinning the input crank, I could analyze the "foot path" (Locus).
3. Torque & Interference: The simulation allowed me to see if the spinning crank would hit the structural frame during a full 360-degree turn. I adjusted the spacing in the software to ensure a collision-free rotation.

Before building the full machine, I had to test the physics of the single leg. I built a rapid prototype to test the crank radius.

The "Spin" happens at the center knee joint. In this step, I realized that if the central crank spins too fast or with too much friction, the legs would buckle. This led me to design looser tolerances for the final 3D printed parts to ensure the rotation was smooth and continuous.

You can actually see in the first gif that my initial prototype didn't generate a fully flat walking path—I had mixed up the values for two of the joints by <0.1 inches! I'm very glad I tested this before printing the final version.

The beauty of this project is that it starts as a "Kit of Parts." Because the mechanism relies on specific geometric ratios, organization was just as important as the printing itself.

The Manufacturing Process:

1. 3D Printing the Kit: I exported my components from Fusion 360 to the printer. To avoid confusion during assembly, I systematically labeled each linkage arm directly in the CAD file before printing.
2. Efficient Nesting: I used Fusion 360's Manufacture workspace (specifically the 3D Print Helper) to nest the parts efficiently on the print bed. This allowed me to print multiple legs at once while minimizing support material and PLA waste.

Sustainability Strategy: Beyond efficient manufacturing, the Crawler aims to achieve sustainability in two distinct ways:

1. Energy Harvesting: We aren't burning fuel to move; we are cooking kebabs and using the byproduct (waste heat) to power the engine.
2. Regenerative Function: The walking motion—driven by the spin—is designed to aerate (till) compacted topsoil and distribute compost, helping desert flora recover from soil erosion and extreme heat.

Assembling the Crawler is a bit like skewering kebabs. It relies a lot on Rotational Symmetry.

The crawler has multiple pairs of legs. To keep the building from tipping over, the spinning cranks are offset by 120 degrees (phase shifted).

1. 0 Degrees: Front legs lift.
2. 120 Degrees: Middle legs plant.
3. 240 Degrees: Back legs push.
4. and so forth

I assembled the legs onto the wooden dowel crankshaft, ensuring they were clocked correctly so the rotation resulted in a smooth, wave-like forward motion.

Design Note: To guarantee kinetic stability, the design requires a minimum of 6 pairs of cranks (legs). This configuration ensures that at any point in the rotation, there are always at least two points of contact with the ground, creating a stable base that prevents the model from tipping.

In this project, the architecture is the machine. The design is organized entirely around the Central Hearth.

1. The Engine Room: The Kebab grill sits at the exact center of gravity. It is the "heart" of the building—both the social gathering point for dinner and the mechanical engine for movement.
2. Suspension: The kitchen modules hang from the chassis, creating a stable platform that isolates the diners from the vibration of the walking legs.
3. The Ecological Loop: As the heat spins the engine and moves the building, the legs till the soil below. Organic waste from the meal drops through the open floor plan, where it is immediately mixed into the earth by the moving feet. The building eats, moves, and fertilizes simultaneously.

The Crawler is a testament to the power of the circle. By harnessing thermal rotation, we transformed a simple Kebab grill into a vehicle for ecological regeneration.

What I Learned:

1. Energy Conversion: I learned that "spinning" is the universal language of mechanics. Once you can turn heat into a spin, you can make anything happen—even a walking building.
2. Simulation is Vital: Simulating the crankshaft in Fusion allowed me to visualize the invisible flow of energy from the center out to the legs.

This project shows that engineering isn't just about efficiency; it's about connecting our daily rituals (like cooking) to the health of our planet.

Thank you for reading!

I've uploaded all the parts I used to construct the leg of my Crawler in case you want to tinker with the mechanism and build your own.

Assembly Tip: When printing the linkages, I included washers in the file set. These should be used to stack the linkages at the joints. They are crucial for ensuring the tolerance is tight throughout the mechanism while preventing the PLA parts from grinding against each other.

Download the files below, fire up your printer, and get those gears turning. Happy building!

This project stands on the shoulders of Theo Jansen, whose Strandbeest work taught me everything I know about kinetic linkages. You can read more about his work here.

Image Credit: Joshua Tree Background by Jeff Sullivan on Flickr.