Camera can't help since it's dark
A camera could, with some IR illumination.
However, if you're that close to your deadline, an Arduino is not the best choice.
http://instruct1.cit.cornell.edu/courses/ee476/FinalProjects/s2010/aip23_kaf42/aip23_kaf42/index.html
My usual comment is, if you have to ask the question, you're probably not the person to do it.