I Gave Codex Eyes: It Flashed an ESP32 and Made a Cat Printer Print Itself

cloudkats · reddit · 2026-09-14

The author wanted to turn a tiny Bluetooth cat printer into a Wi-Fi printer using an ESP32-S3. He wired up the hardware, pointed his MacBook camera at the printer and the dev board, and gave Codex (GPT-5.6) access to the setup, including the terminal and camera.

Once ready, he gave it the goal, asked it to test and keep a checklist, then went AFK. Codex could send a print job, take a camera snapshot, and check what actually came out on paper, letting it use physical results while working through tests. It wrote and flashed the ESP32 firmware and built a webpage for previewing and printing images over Wi-Fi. The author checked in along the way and helped with final physical checks.

For the last test, he asked it to photograph the printer and print that photo. The printer printed itself. What surprised him was how far the agent could get once it had hardware access and a way to verify its own work.

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