Chronos Ledger (prototype)

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  Chronos Ledger interface for registering a product on a blockchain, requiring firebase and wallet connection.

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  MetaMask transaction request to register a product hash (CardioCare Plus) on the Chronos Ledger blockchain (Sepolia network).

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  Registering generates QR code for the product and allows the admin to input product details and download the QR image.

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  Consumer view for verifying a product by entering its ID, scanning a QR code, or uploading a QR image.

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  Consumer view on the Chronos Ledger verifies that Product ffBGdBa06v3robOes6vW (Medicine X) is Authentic.

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  Audit Access is Denied because the required Auditor Web3 Wallet is Disconnected. Specific wallet address needed.

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  Displaying an Audit Summary of 3 batches. Some for manual review due to a label mismatch, etc. Mock.

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  Displays the Original Registration details.

What were you building?

I was building Chronos Ledger, a blockchain-based QR verification system meant to securely authenticate documents and digital assets. The idea was to make verification simple — just scan a QR and confirm its legitimacy via a tamper-proof ledger. It’s part of a larger goal to bridge how we interact with trust and proof online, without depending on centralized authorities.

How did it evolve?

This project actually started as a sem-old idea from an ideathon — one I’d sketched out but never really built. This hackathon gave me the push I needed to take it from an idea to something tangible. At first, I was just experimenting with concepts: smart contracts, Firestore, and basic QR workflows. Then I found myself learning more about Hyperledger, backend linking, and data signing, which gradually shaped the prototype into something real.

Even though I couldn’t fully finish the MVP as I’d planned, I decided to submit it anyway. The hackathon itself emphasized how tough it can be to ship a functional prototype under pressure or not — and I felt that just getting it this far mattered more than having every part polished. And this gave me the push to just go ahead and submit it (hopefully, I submit it before the deadline).

Why does it matter?

Verification systems today rely on trust in platforms, not proof. Chronos Ledger tries to shift that by letting data itself be the proof — a timestamped, traceable record anyone can verify. For me personally, this project mattered because it marked a turning point. I’ve only recently started getting into building real things beyond theory, and this was the first time I felt like I was piecing together code, blockchain logic, and design into a working idea.

What it does

Chronos Ledger uses blockchain to verify and timestamp pharma supply chain documents via secure QR codes.

How we built it

Built with React + Firebase + Solidity on Sepolia. Integrated MetaMask for wallet auth and on-chain hash verification.

Challenges I ran into

Oh, where do we start 😭 —

-Getting the QR reader to properly detect uploaded images (it refused at first).

-Firestore security rules + async reads clashing with wallet state.

-Blockchain transactions taking longer than expected to confirm.

-Handling MetaMask network switching logic for Sepolia.

-Tailwind occasionally breaking UI alignment mid-build.

-Balancing between hackathon deadlines and finishing the MVP logic.

Accomplishments to be proud of

Got a working blockchain verification flow!

What I learned

Hands-on with smart contracts, wallet integration, and managing async data between web and blockchain.

What's next for Chronos Ledger (prototype)

Implementing full QR recognition and auto-verification.

Project demo video available inside the github repo.

Built With

• ethers.js
• firebase
• firestore
• metamask
• react
• solidity
• tailwindcss
• typescript
• vite