Ethereum Game Box: a tabletop console played by tapping NFC wallet badges

A Raspberry Pi console where friends tap NFC wallet badges to stake test USDC on games, with results signed by a hardware key and paid out by contracts on Ethereum's Sepolia testnet.

@george

ethereum-game-box.pages.devvisit ↗

process.log6 fields

toolsClaude Code (Claude Opus)

iterationsMany attempts

several hundred small changes across contracts, Workers, the Pi app and firmware

time36

%_ai100

me 0

ai 100

self-reported · generously rounded

# how_it_was_made

I built this at ETHGlobal Mumbai for a table of friends who have no wallet app, no ETH for gas and no transaction pop-ups: they hold HaLo NFC badges, and a tap is their consent to stake. I chose the hardware (a Pi 5 with a touchscreen, ESP32 tap stations and a HYP2003 USB token that signs with P-256) and the on-chain design: ENS names for players, Box licenses and expiring champion titles, a Cloudflare relayer that pays gas, and a 0G AI judge for store games, with a refund anyone can trigger if a match sits unsettled for an hour. Claude Code wrote most of the Solidity contracts and Foundry tests, the Cloudflare Workers, the Box server and screen, and the browser demo that simulates the Box. I tested each feature on the Pi with real badges before calling it done.

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# prompting_approach

I kept a project plan page and a short rules file that Claude Code read every session: one chain for contracts, addresses only from a deployments file, keys never printed, small typed modules with no copy-paste. I asked for one small change at a time and had it run typechecks and tests before each change landed.