How to use Codex to prototype a shoulder robot
Codex brought a shoulder robot's face, voice and movement to life on ESP32 electronics. Human print checks exposed tolerances; assembly was still ahead.
uglyrobot.dev
Original prompt
Shared by the source author. See source notes for context.
Your arms and legs suck.
Reach people exploring AI agents
See placements →What happened
Face, voice and motion worked on the real electronics, and parametric body files were ready for further prints. Complete assembly and conference operation remained unfinished.
Reported by Aaron Edwards — Personal blogHow the agent did it
- Edwards supplied exact hardware and reviewed Codex's wiring, power and enclosure choices.
- Codex combined expressions, voice and movement on the ESP32-S3 electronics.
- The maker reviewed renders and early prints while leaving complete assembly as an explicit unfinished gate.
Where a person stepped in
Edwards selected parts, judged expressions and renders, checked wiring and attempted prints; complete assembly and conference operation remained future gates.
Aaron Edwards used Codex to prototype a small robot intended to sit on his shoulder at conferences. He supplied the exact purchased parts and asked the agent to reason across power, pin assignments, motors, voice output and the space needed inside a printed body.
The first visible result was a set of animated expressions on an ESP32-S3 display. Edwards adjusted eye size, mouth position, blinking and other details while Codex translated that feedback into drawing coordinates and timing. The agent combined the face experiments with Wi-Fi, the DocsBot Voice API, speaker output and movement in one program running on actual electronics.
OpenSCAD supplied a parametric enclosure around the screen, buttons, speaker, motors and neck wiring. Blender MCP rendered revisions so Edwards could reject proportions before printing. Physical attempts still exposed fused supports, shrinking holes and stiff cables that the previews had not resolved.
The source reports working face, voice and motion on the bench and printable body files. It does not report a completed assembled shoulder robot or a successful conference day. Edwards remained responsible for wiring, appearance and physical acceptance, with assembly tolerances still the next checkpoint.
Prompt
Original prompt
Source: Personal blog · Aaron Edwards
Frequently asked questions
What already worked?
Face expressions, voice and movement on the actual electronics.
Why use parametric CAD?
Dimensions could be revised around purchased parts and wiring clearance.
Was the robot conference-ready?
No. Complete body assembly and conference operation remained future checks.
More details
About this account
Edwards supplied exact hardware and reviewed Codex's wiring, power and enclosure choices. Codex combined expressions, voice and movement on the ESP32-S3 electronics.
Original account opened. Expressions, voice and motion worked on electronics; the complete printed body had not yet been assembled. Original excerpt is the author's actual visual-design feedback. Original prompt excerpt.
Credit: Aaron Edwards — Personal blog
Source published 3 Aug 2026
Source checked 14 Oct 2026
Tools and topics
Codex · ESP32-S3 · OpenSCAD · Blender MCP · DocsBot Voice API
Robot prototype · Physical tolerances
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.