🧍‍♂️ EthMan

ETH Man 🧍‍♂️ has started borning on Arbitrum mainnet 🎉 !

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ETH Man reacts to live ETH price using Chainlink oracles! He is happy 🙂 when it's up 📈 and sad 🙁 when it's down 📉 than the previous value. (Dynamic face, colors on chain SVG NFT).

150+ already minted 🫣 🫣!

Made with scaffold-eth ❤️

Mint it on: https://ethman-sb.surge.sh/

The price is only 0.001 AETH and everything goes to https://buidlguidl.com/ (web3 Builders community)

View the collection on Opensea: https://opensea.io/collection/eth-man-v2

Verified Contract : https://arbiscan.io/address/0x28E1679b0b5CAbd4F494278171cEDcB7134D5DF2#code (Also available and verified on https://sourcify.dev/ )

For Developers 👋

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🏄‍♂️ Getting Started

Prerequisites: Node (v16 LTS) plus Yarn and Git

clone/fork 🧍‍♂️ ETH Man:

git clone https://github.com/technophile-04/ethMan.git

install:

cd ethMan
yarn install

Introduction

This repo shows you how to generate Dynamic SVG NFTs based on live Chainlink's Data Feeds.

Take a look at ETHMan.sol at packages/hardhat/contracts.

AggregatorV3Interface public immutable i_priceFeed;

i_priceFeed holds the contract address of price feed from which it will be getting live price from. Checkout all the available price feeds here.

  /* == states == */
  // updates with new price every time someone mints the token 
  uint256 private lastPrice = 0;
  // each Token ID has HUE associated with it, which decides the colors of different body parts of ETH Man 🧍‍♂️
  mapping(uint16 => uint16[7]) public tokenIdToHue;
  // holds the randomNumber for tokenId generated at mint
  mapping(uint16 => uint256) public tokenIdToRandomNumber;
  // Check if particular token ID is happy or not
  mapping(uint16 => bool) public isHappy;

mintItem() function :

(
  ,
  /*uint80 roundID*/
  int price,
  ,
  ,
  /* uint startedAt */
  /*uint timeStamp*/
  uint80 answeredInRound
) = i_priceFeed.latestRoundData();

if (uint256(price) > lastPrice) {
  isHappy[id] = true;
  lastPrice = uint256(price);
} else {
  // by defalut its false
  // isHappy[id] = false;
  lastPrice = uint256(price);
}

This gets the live price from data feeds. Learn more about the function latestRoundData here and updates isHappy mapping based on previous and current price

uint16[7] memory HUES = [0, 60, 120, 180, 240, 300, 340];

This values represent the angles in the color wheel which represents a color check it out here, This HUES array will be reordered randomly below...This reordered HUES array will decide the colors of ETH Man 🧍‍♂️.

// Calculating pseudoRandomNumber using price also to increase entropy
uint256 pseudoRandomNumber = uint256(
    keccak256(
        abi.encodePacked(
            msg.sender,
            address(this),
            block.chainid,
            id,
            block.timestamp,
            block.difficulty,
            price
        )
    )
);

// reorder the HUES randomly
for (uint256 i = 0; i < 7; i++) {
  uint256 randomIndex = i + ((pseudoRandomNumber + answeredInRound) % (7 - i));
  uint16 temp = HUES[randomIndex];
  HUES[randomIndex] = HUES[i];
  HUES[i] = temp;
}

// Assigning HUES and randomNumber for particular ID
tokenIdToHue[id] = HUES;
tokenIdToRandomNumber[id] = pseudoRandomNumber;

Other functions are self explanatory and a bit of maths, feel free to reach out if you face any difficulty 🙌 Twitter

Using Mocks for local deployment

Taking a look at constructor(address _priceFeed) it need an address of priceFeed to get the latest price.To test out locally we have created Mock contract, checkout /packages/hardhat/contracts/tests/MockV3.sol which we will be deploying on local hardhat chain which will Mock the actual AggregatorV3(Price feed contract).

Look at 00_deploy_Mocks.js in packages/hardhat/deploy/ it deploys MockV3 only when you are using your chain as localhost

Checkout out 01_deploy_ETHMan.js in packages/hardhat/deploy it uses MockV3 address as price feed if we are using local chain, If its not local chain then it uses the AggregatorV3 contract address configured in helper-hardhat-config.js at packages/hardhat

Now when you run yarn deploy (make sure your local chain is running) this is will check your defaultNetwork in hardhat.config.js if its localhost then it will deploy MockV3 and pass its address to EthMan contract and if its not localhost it will use address AggregatorV3 configured in helper-hardhat-config.js at packages/hardhat

Using scripts to mintNFTs and checking the generated NFTs

in a new terminal window, (Make sure your local chain is running and have ran yarn deploy )

cd ethMan
yarn mintNFTs

This will mint 10 NFTs, checkout mintNFTs.js in packages/hardhat/scripts it increases the price every even mint to get happy faces

To get the tokenURIs run of first 10 tokenIDs run :

cd ethMan
yarn getTokenURIs

This will log the tokenURIs for first 10 tokenIDs you can copy the tokenURI and paste it in browser to check out metadata 😁

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Running Locally :

in a first terminal window, start your 👷‍ Hardhat chain:

cd ethMan
yarn chain

in a second terminal window, start your 📱 frontend:

cd ethMan
yarn start

in a third terminal window, 🛰 deploy your contract:

cd ethMan
yarn deploy

You are ready to go 🚀

📱 Open http://localhost:3000 to see the app

Contact

Feel free to reach out if you have any doubts 🙌

Discord : Shiv Bhonde#3592