张高兴的 Windows 10 IoT 开发笔记：HC-SR04 超声波测距模块

张高兴

发布于 2018-05-18 07:52:33

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代码可运行

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代码可运行

　　HC-SR04 采用 IO 触发测距。下面介绍一下其在 Windows 10 IoT Core 环境下的用法。

　　项目运行在 Raspberry Pi 2/3 上，使用 C# 进行编码。

1. 准备

　　HC-SR04 ×1

　　Raspberry Pi 2/3 ×1

　　公母头杜邦线 ×4

2. 连线

Vcc - 5V

Gnd - GND

Trig - GPIO 17 - Pin 11

Echo - GPIO 27 - Pin 13

3. 代码

　　GitHub : https://github.com/ZhangGaoxing/windows-iot-demo/tree/master/HC_SR04Demo

　　你需要在项目中添加一个 C# 代码文件 HCSR04.cs，将下面的代码复制粘贴，并且不要忘记添加引用 Windows IoT Extensions for the UWP

using System.Diagnostics;
using System.Threading.Tasks;
using Windows.Devices.Gpio;

namespace HC_SR04Demo
{
    class HCSR04
    {
        private int sensorTrig;
        private int sensorEcho;

        private GpioPin pinTrig;
        private GpioPin pinEcho;

        Stopwatch time = new Stopwatch();

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="trig">Trig Pin</param>
        /// <param name="echo">Echo Pin</param>
        public HCSR04(int trig, int echo)
        {
            sensorTrig = trig;
            sensorEcho = echo;
        }

        /// <summary>
        /// Initialize the sensor
        /// </summary>
        public void Initialize()
        {
            var gpio = GpioController.GetDefault();

            pinTrig = gpio.OpenPin(sensorTrig);
            pinEcho = gpio.OpenPin(sensorEcho);

            pinTrig.SetDriveMode(GpioPinDriveMode.Output);
            pinEcho.SetDriveMode(GpioPinDriveMode.Input);

            pinTrig.Write(GpioPinValue.Low);
        }

        /// <summary>
        /// Read data from the sensor
        /// </summary>
        /// <returns>A double type distance data</returns>
        public async Task<double> ReadAsync()
        {
            double result;

            pinTrig.Write(GpioPinValue.High);
            await Task.Delay(10);
            pinTrig.Write(GpioPinValue.Low);

            while (pinEcho.Read() == GpioPinValue.Low)
            {

            }
            time.Restart();
            while (pinEcho.Read() == GpioPinValue.High)
            {

            }
            time.Stop();

            result = (time.Elapsed.TotalSeconds * 34000) / 2;

            return result;
        }

        /// <summary>
        /// Cleanup
        /// </summary>
        public void Dispose()
        {
            pinTrig.Dispose();
            pinEcho.Dispose();
        }
    }
}