C#控制Arduino LED、Arduino傳送超音波測距數值至C#

本篇文章為C#傳送字元至Arduino、Arduino回傳字串至C#續文
修改串列埠連線設定方式，取消連線按鈕，改為直接由下拉式選單選擇後連線
新增Arduino回傳超音波測距數值至C#的功能

C#

程式碼
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;


namespace _0150531
{
    public partial class Form1 : Form
    {
        string dis, text2;
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            serialPort1.BaudRate = 9600;
            serialPort1.Parity = Parity.None;
            serialPort1.DataBits = 8;
            serialPort1.StopBits = StopBits.One;
            button1.Enabled = false;
            button2.Enabled = false;
            button3.Enabled = false;
            comboBox1.Items.AddRange(SerialPort.GetPortNames());
            label1.Text = "PC狀態：尚未連線";
        }
        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            serialPort1.PortName = comboBox1.Text;
            serialPort1.Open();
            comboBox1.Enabled = false;
            button1.Enabled = true;
            button2.Enabled = true;
            button3.Enabled = true;
            timer1.Enabled = true;
            label1.Text = "PC狀態：連線中";
        }
        private void button1_Click(object sender, EventArgs e)
        {
            serialPort1.Write("0");           
            comboBox1.Enabled =true;
            button1.Enabled = false;
            button2.Enabled = false;
            button3.Enabled = false;
            timer1.Enabled = false;
            label1.Text = "PC狀態：斷線中";
            label2.Text = "Arduino回傳：";
            serialPort1.Close();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            serialPort1.Write("1");
            button3.Enabled = true;
            button2.Enabled = false;
            label1.Text = "送出指令：LED ON";
        }
        private void button3_Click(object sender, EventArgs e)
        {
            serialPort1.Write("0");
            button2.Enabled = true;
            button3.Enabled = false;
            label1.Text = "送出指令：LED OFF";
        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            label2.Text = text2;
        }
        private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            dis = serialPort1.ReadLine();
            if (dis.IndexOf('C') == 0)
                text2 = "Arduino回傳:" + dis;
            else
                text2 = "wrong";
        }
    }
}

Arduino
這裡不用 Arduino 內建的 Ping 範例，而是使用 HC-SR04 Ultrasonic Sensor Library
這個 library把測距的公式都包成了函式庫，較方便使用
使用時必須先將下載的壓縮檔解壓縮
將 HCSR04Ultrasonic整個檔案夾複製到Arduino的libraries

#include <Ultrasonic.h>
#define TRIGGER_PIN  11
#define ECHO_PIN     12
Ultrasonic ultrasonic(TRIGGER_PIN, ECHO_PIN);
String dis;
void setup() {
   Serial.begin(9600);     // 開啟 Serial port, 通訊速率為 9600 bps
   // 初始化 LED 接腳
   pinMode(13, OUTPUT);
}      
void loop() {
   // 檢查是否有資料可供讀取
   if (Serial.available() > 0) {
     char inByte = Serial.read();
     switch (inByte) {
     case '0':   
       digitalWrite(13, LOW);
       break;
     case '1':
       digitalWrite(13, HIGH);
       break;
     default:
       digitalWrite(13, LOW);
     }    
   }
   else{
     distance();
   }  
}
void distance()
{
  float cmMsec;
  long microsec = ultrasonic.timing();
  cmMsec = ultrasonic.convert(microsec, Ultrasonic::CM); // 計算距離，單位: 公分
  dis=String(cmMsec);
  Serial.println("CM:"+dis);
  delay(50);
}

結果

上述的作法有一些問題存在
C#的計時器用來每隔一段固定時間顯示label2.Text
即表單上變更顯示Arduino回傳字串的時間間隔是由C#的計時器來決定
並非是串列埠收到data即變更顯示label2.Text
另外 當按下斷線按鈕時 很可能 serialPort1_DataReceived還在執行
(??不確定 但的確出現當掉的狀況)

因此變更作法
不再使用計時器固定時間變更顯示label2.Text
直接當串列埠收到資料時 即變更顯示label2.Text
但是 在serialPort1_DataReceived中採用透過 delegate 及 Invoke 來執行 addData()
這是因為 Windows Forms 是 Multi-threading 的機制
如果不這麼寫，直接在 serialPort1_DataReceived 把資料給label2
會遇到「跨執行緒作業無效」的錯誤
另外將計時器的角色做修改
利用 test2作為判斷 當test2=1時 addData()可執行
test2=0 則否
當按下斷線按鈕時 令test2=0 且啟動計時器
此時  addData()便不再執行
直到計時器時間到 再執行斷線serialPort1.Close();

結果
(1)當C#收到data即變更顯示
(2)解決按下斷線按鈕時出現當掉的狀況

修正後程式碼
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;


namespace _0150531
{
    public partial class Form1 : Form
    {
        int test = 1;
        string dis, text2;
        public delegate void AddDataDelegate();
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            serialPort1.BaudRate = 9600;
            serialPort1.Parity = Parity.None;
            serialPort1.DataBits = 8;
            serialPort1.StopBits = StopBits.One;
            button1.Enabled = false;
            button2.Enabled = false;
            button3.Enabled = false;
            comboBox1.Items.AddRange(SerialPort.GetPortNames());
            label1.Text = "PC狀態：尚未連線";
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            test = 1;
            serialPort1.PortName = comboBox1.Text;
            serialPort1.Open();
            comboBox1.Enabled = false;
            button1.Enabled = true;
            button2.Enabled = true;
            button3.Enabled = true;
            label1.Text = "PC狀態：連線中";
        }

        private void button1_Click(object sender, EventArgs e)
        {
                serialPort1.Write("0");
                comboBox1.Enabled = true;
                button1.Enabled = false;
                button2.Enabled = false;
                button3.Enabled = false;
                timer1.Enabled = true;
                test = 0;               
        }

        private void button2_Click(object sender, EventArgs e)
        {
            serialPort1.Write("1");
            button3.Enabled = true;
            button2.Enabled = false;
            label1.Text = "送出指令：LED ON";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            serialPort1.Write("0");
            button2.Enabled = true;
            button3.Enabled = false;
            label1.Text = "送出指令：LED OFF";
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            serialPort1.Close();
            timer1.Enabled = false;
            label1.Text = "PC狀態：斷線中";
            label2.Text = "Arduino回傳：";
        }

        private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            if (test==1)
                this.Invoke(new AddDataDelegate(addData));           
        }
        private void addData()
        {
            dis = serialPort1.ReadLine();
            if (dis.IndexOf('C') == 0)
                text2 = "Arduino回傳:" + dis;
            else
                text2 = "wrong";
            label2.Text = text2;
        }
    }
}

Arduino另一個程式
 #define trigPin  11
 #define echoPin  12

 float echotime, distance;
float obs_dis()
{
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(15);
  digitalWrite(trigPin, LOW);
  echotime=pulseIn(echoPin, HIGH);
  distance=echotime/2/29.1; 
}


 String dis;
 void setup() {
    Serial.begin(9600);     // 開啟 Serial port, 通訊速率為 9600 bps
    // 初始化 LED 接腳
   pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
   pinMode(13, OUTPUT);
 }      
 void loop() {
    // 檢查是否有資料可供讀取
   if (Serial.available() > 0) {
      char inByte = Serial.read();
      switch (inByte) {
      case '0':   
        digitalWrite(13, LOW);
        break;
      case '1':
        digitalWrite(13, HIGH);
        break;
      default:
        digitalWrite(13, LOW);
      }    
    }
    else{
      obs_dis();
      dis=String(distance);
   Serial.println("CM:"+dis);
   delay(50);
    }  
 }