[Pat Fairbank]

We have a custom web app for tracking student attendance. It's both a team participation requirement and a safety issue since we work out of NASA.

When students arrive, they use any lab computer to sign in (the app restricts sign-ins to the lab's IP address to prevent cheating).

To sign out, students have to check with a mentor (so that we can enforce a mandatory 15 minutes of cleanup before leaving). The mentor sends an SMS with the last four digits of the student's school ID to a Twilio number that hooks into the web app, which signs them out. The app checks the origin of the incoming SMS against a whitelist and tracks which mentor signed a student out.

If there's enough interest we'll probably open-source this system later in the summer.