Most people don't keep track of their spare change. The misconception that the coins we carry around possess minimal value causes people to lose track of their "meaningless" change. We wanted to make sure people can track and use their spare change efficiently.

What it does

SpareChange tracks how much change a user has on them by viewing the coins through a phone's camera and helps them in utilizing their change efficaciously. When the user wishes to make a purchase, SpareChange will calculate the best way to use change to pay the cent amount of the purchase.

How we built it

The recognition of coins with the Android's camera was done with OpenCV. We used Node.js for the backend and Twilio to text the user to give feedback and information.

Challenges we ran into

It took a while to configure OpenCV to find circles and get their radii. Once we were able to do that, we were able to distinguish coins.

Accomplishments that we're proud of

We're proud that we successfully used OpenCV for the first time and that we were able to use a variety of matrix manipulation algorithms to detect and recognize objects in the camera's view.

What we learned

We learned how to use OpenCV, and how to interface it with Android. We also learned about Hough Detection and the Canny Algorithm, both of which were utilized in detecting and recognizing the coins.

What's next for SpareChange

We hope to add coins of other currencies to SpareChange, so it is usable for people in other countries as well.

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