A deliberately tiny decision — Keep the cats off the counter — runs through the whole methodology once. Each phase shows two things: the methodical move (how the decision is made) and the layer underneath (where it lands in the data and the architecture). You can try the same decision yourself in the demo cockpit ↗.
Five phases, five layers. 6 requirements, 5 solution types, 5 concrete candidates — one of which fails at the gate. That’s enough to touch every mechanism once.
Mission
The brief
What the system must do — tool-neutral.
Requirements
Requirements
Each requirement on exactly one axis.
Architecture
Solution space
A structural finding splits the space into types.
Solutions
Candidates
Concrete solutions, scored on four axes.
Decision
Verdict
The ranked result under one weighting.
Before any device is named, the methodology pins down what the system must do. Three use cases, the people involved, one stress test — nothing else.
The cats shouldn't get onto the countertop in the first place — not "shoo them down when you catch them."
The direct leap from the floor AND the detour via a chair, stool, or windowsill — both routes count.
Works when no one is home for hours — not just while someone is watching.
| Role | Who |
|---|---|
| Decides & pays | Me — one household, no budget drama, but not play money either. |
| Affected | Two cats and the housemates who use the kitchen every day. |
| The skeptic | The cats themselves — they test every gap, relentlessly and with plenty of time. |
The requirements are the criteria. Each sits on exactly one of the four axes — Gate, Fit, Risk or Cost — which prevents double-counting. The methodology always treats cost separately (4-bucket TCO), never as part of a blended number.
| Requirement | Axis | Tier | Weight |
|---|---|---|---|
| Humane & safe Must not physically harm the cat or create a kitchen hazard (e.g. water near a power socket). Binary: a solution that violates this is out — no matter how well it works. | Gate | hard | K.O. |
| Effectiveness Actually keeps the cat off the countertop. 5 = the cat never gets up there in the first place; 1 = it ignores the measure after a short while. | Fit | critical | 5 |
| Holds unsupervised Works for hours with no one present — the stress test. 5 = runs reliably on its own all evening; 1 = only works while someone is watching. | Fit | critical | 5 |
| Kitchen stays pleasant No constant noise, no clutter or devices on the surface, no smell for the people. 5 = you barely notice it; 1 = the kitchen becomes unpleasant. | Fit | standard | 3 |
| Unobtrusive Ideally near-invisible, no eyesore on the countertop. A pure plus, not a deal-breaker. | Fit | nice-to-have | 1 |
| Robustness / habituation Does it stay effective, or do clever cats learn to work around it while batteries die unnoticed? 5 = robust, no habituation effect; 1 = quickly outsmarted or silently fails. | Risk | standard | 3 |
Phase 3 partitions the space into a few solution types (architectures) — still tool-neutral. They emerge from forks: some are already closed, one stays open and sharpens the space live.
| Solution type | What |
|---|---|
| Buy an off-the-shelf device | Buy a ready-made deterrent — a motion-triggered air blast, ultrasonic emitter, or a textured mat. One-time hardware, possibly refill cartridges. |
| Smart device on subscription | An app-controlled camera/deterrent device on subscription — a recurring monthly fee plus the purchase. The only rental option. |
| In-house build anchor | Build it yourself: a motion sensor + buzzer, or a self-made physical barrier. Costs mostly my time. |
| Catwood (open-core build hub) | The open build path: one deterrent hub (Catwood), composed per job from modules — buy or build — on your own box (self-host) or in the cloud. Between an off-the-shelf gadget and a full in-house build. Configure it live in the Konfigurator. |
| Change the environment anchor | Reshape the environment instead of using a device: remove the incentives, physically block the routes up, train. Nearly free, but my time + discipline. |
These four types emerge from a single fork — “Buy something off-the-shelf — or solve it yourself?” Pull it in the cockpit and the rail narrows from four to two: buy ready-made keeps the bought types, solve it yourself the built ones. That prune is exactly what the kernel does.
Only now are the types filled with concrete products and scored on Gate · Fit · Cost · Risk. One solution is configurable (the ready-made device fans out into three variants), and one fails the gate on purpose — to show what the gate does.
| Solution | Kind | Solution type | Status |
|---|---|---|---|
| Off-the-shelf deterrent device 3 variants Buy it ready-made, set it up once, done. Air blast is the most effective but hisses; the mat is unobtrusive but weaker. |
buy | Buy an off-the-shelf device | live |
| Smart camera + subscription Camera + monthly subscription. Dependent on the app, Wi-Fi, and the vendor — when the subscription lapses, the device is dead. |
rent | Smart device on subscription | live |
| In-house build (Arduino + buzzer) Anchor — the maximal bespoke variant. Shows where the DIY ceiling lies; rarely the winner. |
build | In-house build | live |
| Change the environment (clear out + block) Anchor — the passive variant. Maximally pleasant + unobtrusive, but weaker than an active device when unsupervised. |
build | Change the environment | live |
| Electric shock mat Eliminated by the humane gate. Stays in the comparison only to show what the gate does. |
buy | Buy an off-the-shelf device | Gate ✗ |
The kernel rolls Fit, cost and Risk up under one scenario (€200/day, 3 years amortization) into a verdict — and re-ranks live as you turn the weighting. The cockpit ships presets for this:
Fit ×1 · Cost ×1 · Risk ×1
Fit ×1 · Cost ×2 · Risk ×1
Fit ×2 · Cost ×1 · Risk ×1
Fit ×1 · Cost ×1 · Risk ×2
This one small decision touched every one of the five architecture layers — the methodology phases and the build plan are two views on the same system.
| Layer | In this example |
|---|---|
| Contract | The schema that demo/*.json validates against — four axes, one shape-truth. |
| Kernel | The pure math: gate elimination, Fit weighting, TCO roll-up, ranking. |
| Shell | The cockpit you clicked through — stations, forks, matrix, verdict. |
| Template | The copy-me scaffold such a cockpit is born from. |
| Instance | demo/ itself — the filled data of this cats decision. |