NoSleep

App.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <appSettings>
    <add key="Distance" value="10" />
    <add key="Timeout" value="1:00" />
  </appSettings>
</configuration>

Configuration.cs

using System;
using System.Configuration;

namespace NoSleep
{
    static class Configuration
    {
        public static int Distance
        {
            get
            {
                int distance;
                bool valid = int.TryParse(ConfigurationManager.AppSettings["Distance"], out distance);
                return valid ? distance : 10;
            }
        }

        public static TimeSpan Timeout
        {
            get
            {
                TimeSpan timeout;
                bool valid = TimeSpan.TryParseExact(ConfigurationManager.AppSettings["Timeout"], @"m\:s", null, out timeout);
                return valid ? timeout : TimeSpan.FromMinutes(1.0);
            }
        }
    }
}

Program.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace NoSleep
{
    class Program
    {
        static void Main(string[] args)
        {
            EventWaitHandle done = new ManualResetEvent(false);
            Task.Factory.StartNew(WaitForKeyPress).ContinueWith(task => done.Set());
            JiggleMouse(done);
        }

        private static void WaitForKeyPress()
        {
            Console.WriteLine("Press any key to exit...");
            Console.ReadKey(true);
        }

        private static void JiggleMouse(EventWaitHandle done)
        {
            bool moveRight = true;
            while (!done.WaitOne(Configuration.Timeout))
            {
                int dx = (moveRight ? 1 : -1) * Configuration.Distance;
                User32.MoveMouse(dx, 0);
                moveRight = !moveRight;
            }
        }
    }
}

User32.cs

using System;
using System.Runtime.InteropServices;

namespace NoSleep
{
    static class User32
    {
        public const uint INPUT_MOUSE = 0;
        public const uint MOUSEEVENTF_MOVE = 0x0001;

        [StructLayout(LayoutKind.Sequential)]
        public struct MOUSEINPUT
        {
            public int dx;
            public int dy;
            public uint mouseData;
            public uint dwFlags;
            public uint time;
            public IntPtr dwExtraInfo;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct INPUT
        {
            public uint type;
            public MOUSEINPUT mi;
        }

        [DllImport("user32.dll")]
        public static extern IntPtr GetMessageExtraInfo();

        [DllImport("user32.dll")]
        public static extern uint SendInput(uint cInputs, INPUT[] pInputs, int cbSize);

        public static void MoveMouse(int dx, int dy)
        {
            INPUT[] pInputs = new INPUT[]
            {
                new INPUT
                {
                    type = INPUT_MOUSE,
                    mi = new MOUSEINPUT
                    {
                        dx = dx,
                        dy = dy,
                        mouseData = 0,
                        dwFlags = MOUSEEVENTF_MOVE,
                        time = 0,
                        dwExtraInfo = GetMessageExtraInfo()
                    }
                }
            };
            SendInput(1, pInputs, Marshal.SizeOf(typeof(INPUT)));
        }
    }
}