zana

Open hardware for the physical world — the devices your hub commands.

What's here · The mower · Charging link · Electronics · Build it · Checks

_{FreeCAD · KiCad · 3D-printable · MIT · runs on Aql}

_{Every render in this README is drawn from a mesh tracked in this repo by site/gen_renders.py, and the dimensions are its real bounding box, measured at render time.}

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Zana (Swahili — "tools / gear") is an open-hardware line for the physical world: reference designs for the machines a smart home or business actually runs on — robot mowers, sensor nodes, security and cleaning bots, cameras.

Zana is the body to Aql's brain: every device is meant to drop straight into Aql, the open-source command center. But the designs are open and vendor-neutral, so they work with any compatible control plane. You are not buying into anyone's cloud by printing a wheel.

Important

Status: prototype-stage reference designs. The first device — an autonomous mower — is here as CAD and PCB work recovered from active prototyping, plus one executable engineering study. There is no firmware in this repo, no bill of materials, and no assembly guide. It is not yet a finished, documented, buy-the-parts build. What is here is the geometry, the boards, and the reasoning behind the charging link.

What's here

Area	Contents	State
Chassis & body	FreeCAD bodies across four iterations (mowbot*.FCStd), wheels, casting moulds, motor supports	design files
Drivetrain	Shafts, couplers (including an aluminium variant), GT2 pulley, castor fitting	design files
Electronics	KiCad projects — TRANSMITTER (thru-hole + SMD), MAINBOARD, EMF_SENSOR, RAIN, and the shared IMRANS_LIBRARY symbols	design files
Wireless power	mower/coil-study/ — an inductance and efficiency model for the charging link, in Python	runs; covered by tests
Simulator	mower/simulator/ — C++ (raylib + Bullet, native and WASM) and PyBullet sources for driving over grass	source only — not built, not tested, and it needs a mesh that isn't checked in
Fabrication rigs	The coil winder, PCB mill and UV exposure box built to make the electronics	design files
Firmware	—	not here

The mower

An autonomous robot mower with an inductive charging dock — so there is no connector to corrode in wet grass. Four chassis iterations are tracked, and the older ones are kept deliberately: on a hardware project the design history is the documentation.

	Part	Size (mm)	Notes
	Chassis body	380 × 380 × 41	Iteration 4 — the shell the drivetrain and boards mount into
	Base plate	380 × 380 × 10	Deck the motors, castor and coil receiver bolt onto
	Drive wheel	190 × 40 × 189.9	Printed hub and tread, cast in its own printed mould
	Motor support	60 × 42 × 40	Bracket for the main drive gearmotor
	Castor fitting	90 × 90 × 15	The front swivel mount
	Shaft coupler	30 × 30 × 30	Printed, with an aluminium variant for the load path

Full parts breakdown: mower/README.md.

Formats. .FCStd is the FreeCAD source — edit those. .3mf/.stl are for slicing, .step for any other CAD package, .dxf/.svg are 2D profiles, and .kicad_* are the boards. FreeCAD and KiCad auto-backups are gitignored.

The charging link

mower/coil-study/ models the inductive link from first principles — elliptic integrals for Maxwell mutual inductance between coaxial loops, AC resistance with skin and proximity effects, and the k·Q efficiency solve — for a 200 mm coil at 40 kHz across a 40 mm air gap.

	Option 1	Option 2 — chosen	Option 3
Configuration	Single layer, 8 T	2 layers × 8 T	2 layers × 29 T
Outer diameter	223.8 mm	223.8 mm	295.2 mm
Inductance	30.78 µH	118.46 µH	1288.56 µH
Wire length	5.33 m	10.65 m	45.12 m
Efficiency @ 40 mm	85.7 %	91.5 %	96.4 %
Resonant capacitor	514.4 nF	133.6 nF	12.3 nF

Option 2 wins because it is the same 223.8 mm across as the simple coil and only 1.5 mm thick, but buys 5.9 points of efficiency for one extra winding operation.

Those numbers are not decoration. tests/test_coil_physics.py parses the comparison table out of DESIGN_SUMMARY.md and re-derives every cell from physics.py, then checks the model's own invariants — reciprocity, monotonicity, efficiency bounds. The write-up and the model cannot drift apart without CI going red.

Electronics

Five KiCad projects under mower/PCB/:

• TRANSMITTER — the dock side of the inductive link, in thru-hole and SMD revisions.
• MAINBOARD — the mower's own board.
• EMF_SENSOR — boundary-wire pickup, with a panelised DIP version for milling.
• RAIN — an interdigitated comb electrode. Rain bridges the fingers, conductivity rises, the mower goes home.
• IMRANS_LIBRARY — the shared symbol library the projects draw from.

These boards were not ordered from a fab. The repo also carries the coil winder, the PCB mill and the UV exposure box built to produce them — the part of a hardware project nobody photographs and everybody needs.

Build it

You will want FreeCAD for the mechanical design, KiCad for the boards, and a 3D printer for the printable parts.

1. Open the .FCStd files in mower/ — those are the editable sources.
2. Open the KiCad projects in mower/PCB/. EMF_SENSOR_DIP ships a panelised board and a script for milling it yourself.
3. Slice the .3mf/.stl meshes. The wheel is cast in its own printed mould rather than printed solid.
4. Expect to fill gaps — there is no firmware, no BOM and no assembly guide here.

Checks

Most of this repo is CAD and PCB binaries that no CI can meaningfully verify. What is checkable is checked, and .github/workflows/ci.yml runs it on every push:

pip install -r requirements-dev.txt
python3 -m pytest -q

Three gates, each asserting its own coverage count so it cannot pass by doing nothing:

• tests/test_coil_physics.py — re-derives every number in the coil write-up from the model, and checks reciprocity, monotonicity and efficiency bounds.
• tests/test_repo_integrity.py — every path named in a README exists; no tracked file is an empty husk; every shell script parses; every Python file compiles; no home directory leaked into a checked-in export.
• tests/test_site.py — site/ fetches nothing off-box, every local path resolves after the copy, the type is vendored, and the landing cannot quote a dimension its mesh does not have.

The site

site/ is a self-contained mini-site — no build step, no third-party requests — collected into vulos.org at /products/zana. Its part renders are generated:

python3 site/gen_renders.py     # → site/assets/renders/*.webp + parts.json

That script reads the tracked meshes, projects them orthographically and z-buffers them into transparent renders, then measures each part's real bounding box into parts.json. test_site.py fails if the page ever states a dimension that disagrees with it, so the captions cannot rot.

Ecosystem

• Aql — the brain: the open-source command center that discovers and controls your devices.
• Zana — the body (this repo): the open hardware Aql commands.

Zana devices work with any compatible control plane, and run best on Aql.

Brand

The mark in brand/ is the source of truth. Every icon this repo ships — favicon, PWA and app icons, the mark in the README and on the site — is rendered from brand/logo.svg rather than redrawn, so there is one approved drawing and no second copy to drift.

Copy it outward, never edit a derived copy, and never edit brand/ to match something downstream.

License

MIT — © VulOS. Zana is a VulOS project; source and issues at github.com/vul-os/zana.

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_{vulos — open by design}