Inspiration

One of our team members has trouble staying within their budget. He would often set spending goals at the start of the month but wouldn't be able to stick to it when all of his friends went out to eat and party. We wanted a solution that would force him to stick with his budget without making it seem painful, meaning the product needed to dissuade spending psychologically as well as physically.

What it does

It displays your budget visually when you take your wallet out to pay for something. Before you pay, it shows the effect of your purchase on the budget, giving you a chance to not purchase. If a purchase will go over budget, it won't let you proceed with the transaction, but a manual override will be available as a last resort for emergencies.

How we built it

For the backend of our app, we used Firebase to store the data, Node to set up a server, and Nessie API to provide user data and banking information. The frontend uses react for the mobile app. For our physical device, we have an ESP32 module to receive and transmit data from our app, so it can process transaction data, a screen to visually show the user's budget, a button for confirming transactions, an NFC tag to do the transactions, and a buzzer for recognizing completed transactions. We're also hosting this app on Expo.

Challenges we ran into

Our initial issue was hardware constraints. We had difficulties finding the parts that we needed, so we had to borrow parts from our friends. The next biggest constraint was troubleshooting the electronics, since when we first built it, the screen didn't display the right thing. The last big challenge we faced was making sure our device communicated with our backend properly during a transaction.

Accomplishments that we're proud of

We're proud of making our first real hardware project. None of us had experience in electrical engineering before this event, so getting a device to work is our biggest accomplishment.

What we learned

We learned how to debug wiring issues, maximize our product's effectiveness while being heavily constrained, and connect hardware with software to bring our ideas to the physical world.

What's next for Cash Flow

We will aim to engineer a smaller version so that it actually fits into a wallet or can fully replace one. Hopefully with Capital One's help, we can also add more banking functionality into the app beyond tracking budgets.