A Writer Used Google's Gemini to Design a Cat-Proof Door Lock Cover

A writer at Android Police asked Google's Gemini chatbot to design a 3D-printable cover that keeps a cat from pressing the release button on an electronic door lock. The AI got the measurements nearly right and wrote the design code. But the first version would not have printed, and the hinge needed fixes.

The problem and the setup

The cat had learned that hitting the button on the apartment's lock releases the latch. The door does not swing open, but he keeps trying. The writer wanted a cover that blocks paws and still lets a person use the lock normally.

Instead of learning CAD (computer-aided design, the software used to model physical parts), the writer used the free version of Gemini. It was told to act as an expert engineer and was given two photos of the lock, one marked up with colored lines, plus measurements. The available plastics were TPU, ABS and ASA.

What Gemini produced

Gemini offered three ideas: a hinged flip-up shield, a fixed hood with side access, and a flexible TPU guard that would need a deliberate press. The writer chose the flip-up shield.

It also planned a base frame held on with double-sided tape. The frame leaves the manual override knob free, because that knob turns and should not hold the cover. The writer found that reasoning impressive.

Gemini then wrote code for OpenSCAD, a free tool for building 3D models. The code covered two parts, a base frame and a flip-up cover with hinge pins, a thumb-lift lip and a catch to keep it closed. Gemini also gave printing and assembly steps.

Where it went wrong

Gemini called the model ready to print. It was not. It cannot make the print file itself, so the writer ran the code through OpenSCAD to create one. The design also ignored basics of designing for manufacturing, meaning shaping a part so the printing method can actually make it.

• The bottom needed to sit flat on the printer's build plate.
• Steep overhangs and long unsupported spans can sag, because printers build layer by layer.
• The hinge had design problems that were fixed only after follow-up prompts.

Short corrective prompts fixed the printing flaw and the hinge. Even so, the final fit and hinge were still less than perfect.

What it means for you

The writer sees this as useful for beginners. Gemini can brainstorm options, draft a design and explain unfamiliar terms, and the result can be refined through testing. Within a few prompts, the writer had a full starting point without learning the whole process first.

The catch is that you must know enough to spot what is wrong. Gemini sounded confident about a design that would have failed. For a household fix like this, treat the AI's output as a first draft, not a finished product.