PaintGlobal

PaintGlobal is an on-chain art platform built around a public gallery, physical NFC identity, and NFT auctions, designed specifically for an ETHGlobal-style hackathon environment.

All artworks originate from the painting workshop that took place during the hackathon, making the platform a direct extension of a real-world creative experience. Each participant can upload a single creation, which is then stored (media and metadata) on IPFS and displayed in a shared public gallery where users can explore, vote, and discover other participants’ work through ranking views.

A key component of the experience is the NFC chip embedded in the official hackathon wristband. This chip acts as a unique physical identity layer. Users interact with the platform by scanning their wristband (HaLo-style signing), turning participation into a tangible, event-like interaction rather than a standard Web3 dapp flow.

The platform also features a dynamic leaderboard driven by community engagement. Users can vote on other creations through a Tinder-like swipe interface (like/dislike). Each vote requires verification via the NFC wristband, ensuring one real participant = one voting identity. This creates a fair, sybil-resistant ranking system where the most appreciated artworks naturally rise to the top.

After uploading their artwork, participants can mint their own creation as an NFT. To enable on-chain interactions, users connect a wallet via WalletConnect (e.g., MetaMask). A one-time mapping is then established between the user’s wallet and their wristband NFC chip, effectively binding their on-chain identity to their physical presence at the event.

Once connected, users can participate in an English-style auction system. Bids are placed using funds from the connected wallet, but all actions are tied to the NFC identity, ensuring that bidding activity, settlement, and NFT ownership remain consistent with the physical identity layer. This creates a seamless bridge between the real-world event and on-chain logic.

The interface is a mobile-first, brutalist Next.js frontend designed for live demos, with clear and simple flows: upload artwork, browse the gallery, vote using the wristband, mint NFTs, connect a wallet, and participate in auctions, including finalization once the timer ends.

Together, the smart contracts and UI create a cohesive narrative: a physical wristband becomes a cryptographic identity, a workshop becomes an on-chain gallery, and a hackathon experience evolves into a fully interactive art marketplace.

We built PaintGlobal as a Next.js App Router app using React, TypeScript, and Tailwind, with wagmi + viem as the bridge to the blockchain.

The core idea is that everything revolves around the NFC chip embedded in the official hackathon wristband, making the entire experience native to the event. Every meaningful interaction—identity, voting, and participation—is rooted in this physical chip, ensuring that users are not just anonymous wallets but real, present participants.

To unlock on-chain features like auctions, users can connect a wallet via WalletConnect (e.g., MetaMask). This wallet is then explicitly bound to the NFC chip through a one-time mapping. This creates a strong link between the physical identity (the bracelet) and the financial layer (the wallet), ensuring that the same person who taps the chip is the one interacting and paying on-chain.

Once this binding is established, users can seamlessly participate in English auctions. Bids are placed using the connected wallet, but every action remains tied to the NFC identity, preserving the integrity of the hackathon environment. This allows us to maintain a “hacky but honest” system where participation is both on-chain and physically verified.

On the infrastructure side:

Solidity smart contracts power the core logic: NFT minting, English auctions, and the NFC-linked bidder registry. IPFS (via Pinata) is used to store artwork and metadata in a decentralized way. We leveraged ARC testnet for development and testing, which made it easy to handle auction payments using USDC and implement smooth, automatic settlement flows. WalletConnect, combined with this setup, enabled us to quickly build a fully functional auction system where real funds can be used in a controlled hackathon context.

Finally, the NFC layer (libhalo) ties everything together. We use structured message signing and nonces so that the physical chip can sign interactions that align with the rules enforced by the smart contracts. Next.js Route Handlers act as a simple and reliable relay between the frontend, the NFC layer, and the blockchain.

The result is a system where: a physical chip = identity, a wallet = liquidity, and both are cryptographically bound to create a seamless, trustworthy on-chain auction experience within a real-world event.