how to capture the keyboard input in windows service

i am struggling a lot, to capture the key press input in Windows Service

i have KeystrokeAPI which works in console application,

i wrote the below code in OnStart() of the service

protected override void OnStart()
        {
using (var api = new KeystrokeAPI())
            {
                System.Timers.Timer t = new System.Timers.Timer();
                t.Elapsed += new ElapsedEventHandler(TimerCallback);                    
                t.Interval = 30000;
                t.Enabled = true;
                t.AutoReset = true;
                api.CreateKeyboardHook((character) => {
                   // Console.Write(character);
                    count++;

                });
            }
}

and Event Handler

 protected void TimerCallback(object sender, ElapsedEventArgs e)
    {
        // Display the date/time when this method got called.
        //Console.WriteLine("In TimerCallback: " + DateTime.Now);
        //Console.WriteLine("Count Of Keys: " + count);
        StreamWriter sw = new StreamWriter(@"d:\ChaiKeyAPILog.txt", true);
        sw.WriteLine();
        sw.WriteLine("In TimerCallback: " + DateTime.Now);
        sw.WriteLine("Count Of Keys: " + count);
        sw.Close();
        count = 0;
        // Force a garbage collection to occur for this demo.
        GC.Collect();
    }

as i kept timer, so it diplays the datetime for every given interval of time, but it is not displaying the count of the pressed keys of the keyboard.

i tried it in writing this code in Main() also. but no use.

please help me.. to get the count of the pressed keys for every 1 minute of time In windows services