uses
  Windows, Messages, SysUtils, Classes.....

type


  ......
  protected     { Protected-Deklarationen } //kann auch woanders hin
    FNotifyWnd  : HWND; // wird für Timer gebraucht
    procedure ....


//------------------------ Timer initialisieren -----------------------------------------

procedure XYZ.SetTimer;
begin
  FNotifyWnd := Classes.AllocateHWnd( TimerWndProc );
  SetTimer( FNotifyWnd, 1, 500, nil );
end;                //      |
                    //      ----- Millisekunden

//-------------------------- Timer abschalten -------------------------------------------

procedure XYZ.KillTimer;
begin
  KillTimer( FNotifyWnd, 1 );
  Classes.DeallocateHWnd( FNotifyWnd );
end;

//--------------------------- Timer procedure -------------------------------------------

procedure XYZ.TimerWndProc( var msg: TMessage );
begin
  if (msg.Msg = WM_TIMER) then -> deine Routine
end;

//---------------------------------------------------------------------------------------