[0nly1ife]

You will only have legal problems if your product is successful. Until then Large Company won't notice you. I say finish the project and try and develop a business around it. You already designed the hardware and wrote the firmware, don't abandon that hard work. You have nothing to lose, because odds are, the business will fail (no offense, it just difficult to make a hit product in your first try). In the event that you turn this project into a profitable business, make sure you save enough to cover the legal fees to fight the patent. But really, be proud of yourself if you actually make it that far.

tl;dr don't worry about it until you are making money