Pendulum

For this project, our goal was to implement a social application that would allow industry experts to create and sell "Pendulums" which grant the holder the right to ask and receive answers to their questions on a given topic. Pendulums have a topic for the questions that can be asked, as well as a fee to "recharge" them. Every cycle (length determined by expert who is the issuer), the holder of a pendulum must pay to continue holding the pendulum according to a Harberger tax. This means that The holder sets a price at which they are willing to sell the pendulum at any time, and pay a recharge fee each cycle as a percentage of that price. Experts earn money from the initial sales, as well as transfers of their pendulums. This application ultimately provides a way to directly access the knowledge of experts, while allowing those with expert knowledge to monetize. The Harberger tax also enables speculation and other interesting economic mechanics, since a holders must pay to keep a pendulum while it is always for sale (until the expiration date). After expiration, a pendulum contract becomes a modified, collectable ERC721 token.

We started this project by using the ScaffoldETH 2 framework. We used Next.js for the web application, foundry for our contract infrastructure, and MongoDB for a backend in order to provide easier access to information. Our contracts consist of a factory for pendulums, the pendulum contract, a modified ERC721 for collectability, a registry, and proxies for UUPS upgradability. We used Ethereum Attestation Service to verify all messages (questions and answers) on chain, in order to enforce decentralized accountability for all users on the platform. This is important because the quality of answers that an expert provides will influence the price of their current and future pendulums. We used NextAuth.js for authentication so that experts would be able to register, but all other users can purchase pendulums, ask questions, and interact with the site just by connecting their wallets. We hope to integrate sign in with Ethereum in the future. Our database keeps track of experts, as well as pendulums for low-cost access to data. Importantly, all data is also stored and visible on-chain. We deployed on Base, Optimism, and Zora testnets, with the goal of letting users choose which chain they wish to deploy their pendulums on by selecting a chain in the app.