# Danang Defi Study Group – week #15

By [David Ryan](https://paragraph.com/@drcoder) · 2022-09-08

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Time: 9:30am on 7th Sept 2022 Location: Draper Startup House My Khe Beach, Danang, Vietnam Present: 7 people

Demo: **Flash loans** using Solidity and Javascript. We talked about:

*   The Aave contract on Ethereum mainnet which has a flashloan method, that borrows potentially all of an asset in Aave, but only for the duration of 1 transaction, and charging a 0.09% fee
    
*   Deploying another custom contract to call the Aave flashloan and arbitrage prices between Uniswap and Kyber exchanges
    
*   Scanning Uniswap and Kyber data feeds locally using Javascript. Finding arbitrage opportunities. Submitting them to the custom contract as data. The custom contract then executes the arbitrage, using funds from the flashloan. How if the funds are not returned to Aave, the transaction fails.
    

**Checksums** on Ethereum addresses (such as my address `0x7349d6e55cB3F737249FbAa047C16b826559B127`) – how the mixture of lower case and upper case letters can be used to check if an Ethereum address is valid, and prevent sending assets to the wrong address.

Claiming POAPs using **POAP Delivery**:

[https://poap.delivery](https://poap.delivery)

Viewing POAPs using the **POAP App**:

[https://app.poap.xyz/](https://app.poap.xyz/)

Checking mainnet gas prices at: Watch The Burn (this will probably cease service soon)

[https://watchtheburn.com](https://watchtheburn.com)

My own release of “**Ethereum Merge Fractal NFT**”, to celebrate the Ethereum Merge and raise funds for Ethereum core developers via Protocol Guild. Announcement on Twitter:

[https://twitter.com/davidryan59/status/1566411577095749632](https://twitter.com/davidryan59/status/1566411577095749632)

How to use **ABI Ninja** to mint automatically (instructional video in thread above)

[https://abi.ninja/0xCeaAb19BaB4AdBc831b98A4Cf54A6A85A79218a4](https://abi.ninja/0xCeaAb19BaB4AdBc831b98A4Cf54A6A85A79218a4)

View the whole collection on OpenSea, we talked about how to view and analyse the attributes for rarity value:

[https://opensea.io/collection/mergefractals](https://opensea.io/collection/mergefractals)

I was goaded into minting a YEET degen NFT here:

[https://etherscan.io/token/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13?a=2876](https://etherscan.io/token/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13?a=2876)

And told to list it for sale on OpenSea – it sold!

[https://opensea.io/assets/ethereum/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13/2876](https://opensea.io/assets/ethereum/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13/2876)

We also played a quick round of **Dark Forest** via **DF DAO Grand Prix**, you can check out their Twitter here for announcements of future rounds:

[https://twitter.com/d\_fdao](https://twitter.com/d_fdao)

Thanks everyone for meeting! This was week 15, I don’t think I’ll get time to retrospectively put up meeting notes for weeks 1 to 14, but am happy to revisit any important items from those weeks and get the web links into a future article.

Hopefully the notes and links in this article are a great reminder of what we discussed!

PS - the Ethereum Merge is nearly upon us!

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*Originally published on [David Ryan](https://paragraph.com/@drcoder/danang-defi-study-group-week-15)*