I wouldn't say it requires a projector or smart pens. My school had both the "official" smart board most people know, but also a model of whiteboard that used I

I wouldn't say it requires a projector or smart pens. My school had both the "official" smart board most people know, but also a model of whiteboard that used IR sensors and regular pens. I don't know how expensive they were, as they still were a commercial product sold to schools, but they didn't need a projector or smart pens