FundMe

A decentralized crowdfunding smart contract built with Solidity. The contract allows users to fund the contract with ETH while enforcing a minimum USD contribution. It uses Chainlink price feeds to convert ETH to USD and provides owner-controlled withdrawals.

Overview

FundMe is a Solidity-based crowdfunding smart contract that demonstrates how multiple smart contract concepts can work together in a practical application.

Users can send ETH to the contract as funding, while the contract uses a Chainlink ETH/USD price feed to determine whether the contribution meets the minimum required USD value.

Only the contract owner can withdraw the accumulated funds.

Features

• Accepts ETH contributions from users
• Enforces a minimum contribution of $5 USD
• Converts ETH to USD using Chainlink price feeds
• Tracks contributors using an address array
• Records each contributor's funded amount using a mapping
• Uses a constructor to establish contract ownership
• Uses an onlyOwner modifier to restrict withdrawals
• Uses a reusable PriceConverter library
• Allows the contract owner to withdraw the accumulated ETH
• Resets contributor records after withdrawal

Smart Contract Components

PriceConverter Library

The PriceConverter library contains reusable functions for working with the Chainlink price feed.

It includes:

• getPrice() - Retrieves the current ETH/USD price from the Chainlink price feed.
• getConversionRate() - Converts a given amount of ETH into its USD value.
• getVersion() - Returns the version of the Chainlink price feed.

The library is used in FundMe.sol with:

solidity using PriceConverter for uint256;

Technologies Used: Solidity, Ethereum, Chainlink Price Feeds, Remix IDE, Git & GitHub, Key Concepts Practiced,

Through this project, I practiced and applied: Solidity functions, Arrays, Mapping, Structs, Constructors, Modifiers, msg.sender, msg.value, payable, Data locations, Libraries, ETH transfers using call, Error handling with require, Integer overflow and underflow, Chainlink price feed integration, ETH/USD conversion, Access control, Deployment,

The contract was deployed and tested on:

Network: Sepolia Testnet

Contract Address: 0xa2781417978a775d07f5e839dcc5299065b9c956

Block Explorer: https://sepolia.etherscan.io/tx/0xe2cf71e7e4933602c24b1058a392b695c88527ecbd4821b4ffbff192232d09dd