Home & IoT

Build a family shopping list on an e-ink fridge magnet

A parent had Claude Code write all the firmware for an e-ink touchscreen shopping list that syncs with a phone web app.

By seamus_c on Hacker News · Posted · Added Oct 15, 2026 · 2 sources

Difficulty
IntermediateOur rating
Time to build
Not reportedOur estimate
Monthly cost
Not reported (one-time hardware)
Revenue
Not reportedWe only show revenue the source states

What they did

seamus_c built PaperMono, about 2,400 lines of C++ firmware for an M5Stack PaperMono (ESP32-S3, e-ink touchscreen) that sticks to the fridge and syncs with a phone web page over Wi-Fi. He says it was fully vibe coded with Claude Code; he didn't hand-write it.

How it went

His family uses it day to day, which he says is a first for one of his home projects. The code is on GitHub.

Worth knowing

E-ink needs periodic full refreshes to avoid ghosting; he used the recommended full refresh every 15 interactions. Part of the experiment was whether AI could build for unfamiliar hardware without damaging it.

Builder recipe

Our own starting point, written from the source. Adapt it to your setup.

Stack

  • Claude Code
  • M5Stack PaperMono (ESP32-S3)
  • PlatformIO or Arduino toolchain

Steps

  1. Clone the repo or start from the board's example project.
  2. Ask Claude Code for firmware plus a tiny web app on the same Wi-Fi.
  3. Flash, test ticking items, then tune e-ink refresh behavior.

Starter prompt

Write ESP32-S3 firmware for an M5Stack PaperMono that shows a shopping list on the e-ink screen, lets me tick items by touch, works offline, and syncs with a mobile web page served on the local Wi-Fi.

Open the repo ↗ (opens in new tab)

Tags

Industry Home Hardware

Read the original

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