Sign In/Out Platform

Members,

I will be taking on a new teaching position in the Fall. I will be facilitating
the Content Mastery Center (CMC) at the local high school. I am in the process
of setting up and organizing the center. I am looking for any software or
online program that allows the students to sign in and sign out when visiting
and leaving the CMC. I would like information on something computer based that would
allow the students to sign in individually and allow me to track the students' usage
of the center. At this time, I am not sure that online classroom platforms such as Edu 2.0, Moodle, Blackboard, etc. is what I am looking for. I am more looking for a free software program in which the students can come into the classroom, sign-in, list the subject they are in for, and sign out when they leave. Any ideas you may have would be greatly appreciated.

Thanks,