🏦 On-Chain Piggy Bank - U2U Solaris Mainnet dApp

A timelock savings dApp built for the U2U Hackathon, deployed on U2U Solaris Mainnet.

MVP Link - on-chain-piggy-u2-u.vercel.app

✨ Features

• U2U Solaris Mainnet - Built specifically for U2U Solaris Mainnet

• Timelock Savings - Deposit U2U or ERC-20 tokens with custom lock periods

• No Early Withdrawals - Enforced time-based locking mechanism

• Batch Operations - Withdraw multiple matured deposits at once

• Responsive Design - Works on desktop and mobile devices

🔗 U2U Solaris Mainnet Setup

1. Add U2U Solaris Mainnet to MetaMask

Network Name: U2U Solaris Mainnet
RPC URL: https://rpc-mainnet.u2u.xyz
Chain ID: 39 (hex: 0x27)
Currency Symbol: U2U
Block Explorer: https://u2uscan.xyz/

2. Get U2U Tokens

💎 How to Use

1. Connect Wallet

• Click "Connect MetaMask"

• Ensure you're on U2U Solaris Mainnet

• The app will automatically prompt you to switch networks if needed

2. Deposit U2U

• Enter the amount of U2U you want to deposit

• Set the lock duration in seconds (minimum 60 seconds)

• Click "Deposit U2U"

• Confirm the transaction in MetaMask

3. Deposit ERC-20 Tokens

• Enter the token contract address

• Specify the amount to deposit

• Set the lock duration

• Click "Approve & Deposit" (requires two transactions)

4. Withdraw

• Wait for your deposit to mature

• Click "Withdraw" on matured deposits

• Or use "Withdraw All Matured" for batch operations

🔧 Technical Details

• Frontend: Next.js 15 + React 19 + TypeScript

• Styling: Tailwind CSS 4 with custom animations

• Blockchain: U2U Solaris Mainnet integration

• Wallet: MetaMask compatibility

• Smart Contract: Solidity timelock contract with reentrancy protection

📱 Smart Contract

The dApp interacts with a deployed smart contract on U2U Solaris Mainnet:

• Contract Address: 0x423B1e68C91063a505C6aB4aD7736d6ED6a85aCC

• Chain ID: 39 (0x27)

• Network: U2U Solaris Mainnet

• Features: ETH/ERC-20 deposits, timelock mechanism, batch withdrawals

• Security: Reentrancy protection, proper access controls

🐛 Troubleshooting

Common Issues

1. "Wrong Network" Error

   • Ensure MetaMask is connected to U2U Solaris Mainnet (Chain ID: 39 / 0x27)

   • Use the "Switch to U2U Solaris Mainnet" button

2. "Could not decode result data" Error

   • This usually means no deposits exist yet

   • The app handles this gracefully and shows an empty state

3. Transaction Fails

   • Check if you have sufficient U2U for gas fees

   • Ensure the contract address is correct

   • Verify you're on the correct network

Debug Mode

Open browser console to see detailed error messages and transaction logs.

🎯 U2U Hackathon Features

• U2U Solaris Mainnet - Deployed on U2U Solaris Mainnet for production use

• EVM Compatibility - Uses U2U's EVM layer for Ethereum tooling

• Gas Optimization - Efficient smart contract design

• User Experience - Intuitive interface for DeFi beginners