At work, we use the Common Access Card (CAC) Smartcard for PKI. One of
our work requirements is that we go to the Gym at specific times
during the week to stay/get in shape. The current system used for
attendance is pen and paper, transferred into Excel.

I've been playing around with the idea of using our CACs to "sign in"
to an online database that tracks the certificate name and date &
timestamp. One solution I know how to implement would be with
Infopath, but their digital signature process is too kludgy, and would
take too long for everyone to sign in on one computer.

Is there a way of simply having a user click a Sign-in button, sign
some timestamp info with their CAC and PIN, and then send it to a
database or Sharepoint? I was looking around for some java or
javascript code, but couldn't find any.