CodeIgniter extend user's session expiration time
I believe what you want is actually the default behavior.Take a look at sess_read() and sess_update() in /system/libraries/Session.php
last_activity for an active session is updated every five minutes.
Session expiration is checked with last_activity + sess_expiration < now
So, for the behavior you want, just set your sess_expiration time to 86400 (one day), and you should be all set.
From the User Guide:
$sess_expiration: The number of seconds you would like the session to last. The default value is 2 hours (7200 seconds). If you would like a non-expiring session set the value to zero: 0
Hopefully this is what you're wanting to do?
Are you talking about the Session component in CodeIgniter? You can go to config.php and set $sess_expiration = 7200; (7200 is the default)