Monitoring Inactivity in Delphi

Why not just use the system inactivity monitor?

Create a screen saver
http://www.mindspring.com/~cityzoo/scrnsavr.html
http://delphi.about.com/od/screensavers/
http://www.pcmag.com/article2/0,1759,1180484,00.asp
http://www.delphifaq.com/fq/q2192.shtml
http://community.borland.com/article/0,1410,26652,00.html

Set the screen saver to the Desktop default, using the inactivity time limit you want.

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I probably need a bit more information on what you are trying to do.

1. Do you want to start a timer or reset a timer when mouse/keyboard events happen?
2. Do you want to take some action if the interval between events exceeds some preset limit?
3. What do you want to do when the system goes into power-save mode?
4. What do you want to do when the user logs off?
5. How is your application started?
6. Is your application running as a Windows service?

try this simple code.

function secondsIdle: dword;
var liInfo: TLastInputInfo;
begin
        liInfo.cbSize := SizeOf(TLastInputInfo) ;
        GetLastInputInfo(liInfo) ;
        Result := (GetTickCount - liInfo.dwTime) DIV 1000  ;
end;

Now have a timer set on every 30 seconds:

if secondsIdle > 10000 then begin
   form1.caption:='User has been idle for more than 10 minutes!';
end;

use a TApplication ("Additional" tab in the components list)
and use the "OnIdle" event

I thought this question was about any idle period in any application