CRONLOCK

Smart Locker x402 🔐💰

Pay-per-use smart lockers powered by the x402 payment protocol and blockchain payments.

No apps. No accounts. No subscriptions. Just scan, pay, and unlock.

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What is this?

A proof-of-concept demonstrating autonomous IoT payments using Cronos's x402 protocol. Physical lockers that unlock when you pay with cryptocurrency—showcasing the future of machine-to-machine commerce and pay-per-use infrastructure.

The Problem

Current shared infrastructure (gym lockers, storage units, bike locks) requires:

• Monthly subscriptions you don't fully use
• Complex account setups
• Mobile apps that track you
• Payment methods that exclude many users

Our Solution

Smart lockers that work like parking meters for the digital age:

1. Scan QR code on the locker
2. Pay with crypto (USDC on Base network)
3. Locker unlocks automatically via HTTP 402 response
4. Use for the time you paid - extend anytime
5. Auto-locks when time expires

How x402 Works

The x402 protocol activates HTTP's dormant 402 "Payment Required" status code:

GET /locker/3/unlock
← 402 Payment Required
{
  "amount": "0.05 USDC",
  "recipient": "0x...",
  "duration": "1 hour"
}

[User pays via wallet]

POST /locker/3/unlock
Headers: X-Payment-Proof: 0x...
← 200 OK - Locker Unlocked

The locker becomes an autonomous economic agent—earning money and providing service without human intervention.

Architecture

┌─────────────┐
│   Frontend  │  React + Web3 wallet integration
│  (Scan QR)  │
└──────┬──────┘
       │
       ↓ HTTP Request
┌─────────────────┐
│    Facilitator  │  Node.js payment verification
│   (402 Handler) │  Verifies blockchain transactions
└──────┬──────────┘
       │
       ↓ WebSocket/Serial
┌─────────────────┐
│  ESP32/Arduino│  Controls servo/solenoid
│  (Physical Lock)│  Unlocks on verified payment
└─────────────────┘
       │
       ↓ Smart Contract Events
┌─────────────────┐
│   Cronos Network  │  USDC payments recorded on-chain
│ (Blockchain)    │  Immutable payment history
└─────────────────┘

Tech Stack

• Hardware: ESP32 + Servo motors + RFID
• Smart Contract: Solidity on Cronos (EVM)
• Backend: Node.js + Express + WebSocket
• Frontend: React + wagmi/viem for Web3
• Payment: USDC stablecoin (low fees, fast confirmation)

Use Cases

This architecture extends beyond lockers:

• 🚲 Bike/scooter sharing without apps
• ⚡ EV charging stations - pay per kWh
• 🅿️ Smart parking meters
• 🔧 Tool libraries and makerspaces
• 📦 Package pickup lockers
• 🏢 Co-working space amenities
• 🎮 Arcade machines and entertainment

Anywhere you want pay-per-use without subscription overhead.

Why This Matters

For Users:

• No subscription lock-in
• Pay only for what you use
• Instant access, no signup friction
• Privacy-preserving (no personal data collected)

For Operators:

• Automated revenue collection
• Lower operational overhead
• Global payment acceptance
• Transparent transaction history on-chain

For the Ecosystem:

• Enables machine-to-machine economy
• Micropayments become viable
• Physical world meets Web3
• Foundation for autonomous IoT infrastructure

Demo

[Video demo coming soon]

Live Demo Flow:

1. User scans QR code → Web UI loads
2. Connect crypto wallet (MetaMask/Coinbase Wallet)
3. See locker price: 0.05 USDC per hour
4. Approve payment → Transaction confirms in ~2 seconds
5. Physical lock clicks open 🎉
6. Timer starts counting down
7. Option to extend rental or let it auto-lock

Getting Started

[Setup instructions coming soon]

Built With x402

This project demonstrates Coinbase's x402 open payment protocol - enabling direct, automated payments for digital content and APIs using stablecoins.

Learn more: x402 Protocol Documentation

Team

Built for [Hackathon Name] by [Your Team Name]

License

MIT License - Build upon this freely!

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The future of shared infrastructure is autonomous, permissionless, and pay-per-use.