Program.cs

BlinkStickColorUnderPointer.cs

using System;
using System.Timers;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using BlinkStickDotNet;

namespace ColorUnderPointer
{
    class Program
    {
        private static BlinkStick device;
        private static Timer timer;
        private static Point cursor;
        private static Color color;
        private static Bitmap pixel;

        [DllImport("user32.dll")]
        static extern bool GetCursorPos(ref Point lpPoint);

        [DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
        public static extern int BitBlt(IntPtr hDC, int x, int y, int nWidth, int nHeight, IntPtr hSrcDC, int xSrc, int ySrc, int dwRop);

        static void Main(string[] args)
        {
            device = BlinkStick.FindFirst();
            device.OpenDevice();
            device.SetMode(2);

            cursor = new Point();
            pixel = new Bitmap(2, 2, PixelFormat.Format32bppArgb);

            timer = new Timer(300);
            timer.Elapsed += OnTimedEvent;
            timer.AutoReset = true;
            timer.Enabled = true;
            Console.ReadLine();
            device.TurnOff();
        }

         private static void OnTimedEvent(Object source, ElapsedEventArgs e)
        {
            GetCursorPos(ref cursor);
            color = GetColorAt(cursor);
            device.SetColor(color.R, color.G, color.B);
        }

        public static Color GetColorAt(Point location)
        {
            using (var gd = Graphics.FromImage(pixel))
            {
                using (var gs = Graphics.FromHwnd(IntPtr.Zero))
                {
                    var hSrcDC = gs.GetHdc();
                    var hDC = gd.GetHdc();
                    BitBlt(hDC, 0, 0, 1, 1, hSrcDC, location.X, location.Y, (int)CopyPixelOperation.SourceCopy);
                    gd.ReleaseHdc();
                    gs.ReleaseHdc();
                }
            }

            return pixel.GetPixel(0, 0);
        }
    }
}

This is C# code that allows you to move the mouse pointer around the desktop and have the color under the pointer show in your BlinkStick. It requires BlickStickDotNet.dll reference.