Program.cs

using System;
using Raspberry.IO.Components.Sensors.Distance.HcSr04;
using Raspberry.IO.GeneralPurpose;
using UnitsNet;
using System.Threading;

namespace Test.Components.Sensors.Distance.HcSr04
{
    class Program
    {
        private static GpioConnectionDriver driver;
        private static HcSr04Connection sensor;
        private static GpioOutputBinaryPin triggerGpioPin;
        private static GpioInputBinaryPin echoGpioPin;

        private static int triggerGpioPinSetting = 0;
        private static int echoGpioPinSetting = 0;
        private static int delay = 500;
        private static int readError = 0;

        static void Main(string[] args)
        {
            //Configure GPIO pins bellow or provide in console
            //triggerGpioPinSetting = 20;
            //echoGpioPinSetting = 26;

            //Reads GPIO pins from console
            if (triggerGpioPinSetting == 0)
                triggerGpioPinSetting = GetGpioPin("trigger");
            if (echoGpioPinSetting == 0)
                echoGpioPinSetting = GetGpioPin("echo");

            Console.CursorVisible = false;

            //Creating sensor
            driver = new GpioConnectionDriver();
            triggerGpioPin = new GpioOutputBinaryPin(driver, (ProcessorPin)triggerGpioPinSetting);
            echoGpioPin = new GpioInputBinaryPin(driver, (ProcessorPin)echoGpioPinSetting);
            sensor = new HcSr04Connection(triggerGpioPin, echoGpioPin);

            while(true)
            {
                if (Console.KeyAvailable)
                    KeyPressed();
                
                try
                {
                    //Get data from sensor and print them
                    Length distance = sensor.GetDistance();
                    PrintHeader();
                    PrintData(distance);
                    PrintFooter();
                }
                catch
                {
                    readError++;              
                }
                                
                Thread.Sleep(delay);
            }
        }

        /// <summary>
        /// Console read key support
        /// </summary>
        private static void KeyPressed()
        {
            ConsoleKeyInfo cki = Console.ReadKey();
            switch (cki.Key)
            {
                case ConsoleKey.UpArrow:
                    delay = delay > 50 ? delay - 50 : delay;
                    break;
                case ConsoleKey.DownArrow:
                    delay = delay < 1000 ? delay + 50 : delay;
                    break;
                case ConsoleKey.Escape:
                    Environment.Exit(0);
                    break;                    
            }

            if (Console.KeyAvailable)
                KeyPressed();
        }

        /// <summary>
        /// Get GPIO pins from console
        /// </summary>
        /// <param name="pinName">GPIO pin usage</param>
        /// <param name="message">Error message</param>
        /// <returns></returns>
        private static int GetGpioPin(string pinName, string message = "")
        {
            PrintHeader();
            Console.WriteLine();

            if (!string.IsNullOrEmpty(message))
            {
                Console.WriteLine(message);
                Console.WriteLine();    
            }

            Console.Write(string.Format(" Please enter GPIO pin number for {0} pin: ", pinName));

            string answer = Console.ReadLine();
            int pin;
            bool result = int.TryParse(answer, out pin);
            if(result)
            {
                if (pin > 32)
                    return GetGpioPin(pinName, string.Format(" Error. Value {0} is to big", pin));
                return pin;
            }
            else
            {
                return GetGpioPin(string.Format(pinName, "Error. Unable parse string {0}", answer));
            }
        }

        #region Print Methods

        private static void PrintHeader()
        {
            Console.Clear();
            Console.WriteLine();
            Console.WriteLine(" #################################");
            Console.WriteLine(" # Demo pogram for sensor HCSR04 #");
            Console.WriteLine(" #################################");
            Console.WriteLine();
            if(triggerGpioPinSetting != 0)
                Console.WriteLine(" Trigger pin GPIO{0}", triggerGpioPinSetting);
            if(echoGpioPinSetting != 0)
                Console.WriteLine(" Echo pin    GPIO{0}", echoGpioPinSetting);       
        }

        private static void PrintData(Length length)
        {
            Console.WriteLine(" Reads {0:0.0} per secound [Hz]", 1000.0 / delay);
            Console.WriteLine();
            Console.WriteLine(" Read errors {0}", readError);
            Console.WriteLine(" Length {0,5:0.0} cm", length.Centimeters);
            Console.WriteLine(" Length {0,5:0.0} inch", length.Inches);
        }

        private static void PrintFooter()
        {
            if (Console.WindowHeight < 17)
                return;
            Console.SetCursorPosition(0, Console.WindowHeight - 4);
            Console.WriteLine(" Press arrow up to increase read sppead");
            Console.WriteLine(" Press arrow down to decrease read sppead");
            Console.WriteLine(" Press escape key to exit");
        }

        #endregion
    }
}