C# and Arduino problem with serial port

Question

I would like to establish a communication between my C# program and my Arduino Duemilanove. I tried lot of different tutorials, but none of them were the same, and I'm a little bit confused.

Actually my code is:

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO.Ports;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace InterfaceArduinoWindowsFOrm {
 public partial class Form1 : Form {
 public Form1() {
 InitializeComponent();
 serialPort1.PortName = "COM3";
 serialPort1.BaudRate = 9600;
 serialPort1.Open();
 }
 private void pictureBox1_Click(object sender, EventArgs e) {
 }
 private void tabPage2_Click(object sender, EventArgs e) {
 }
 private void listBox1_SelectedIndexChanged(object sender, EventArgs e) {
 }
 private void toolTip1_Popup(object sender, PopupEventArgs e) {
 }
 private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e) {
 Console.WriteLine("test");
 }
 private void button1_Click_1(object sender, EventArgs e) {
 serialPort1.Write("5");
 Console.WriteLine(serialPort1.IsOpen);
 }
 }
}

Arduino:

/* Sweep
 by BARRAGAN <http://barraganstudio.com>
 This example code is in the public domain.
 modified 8 Nov 2013
 by Scott Fitzgerald
 http://arduino.cc/en/Tutorial/Sweep
*/
#include <Servo.h>
Servo myservo; // Create servo object to control a servo.
// Twelve servo objects can be created on most boards.
int pos = 0;
int message = 0; // This will hold one byte of the serial message
 // variable to store the servo position.
void setup() {
 Serial.begin(9600);
 myservo.attach(9); // Attaches the servo on pin 9 to the servo object
}
void loop() {
 if (Serial.available()) {
 // Check to see if there is a new message
 message = Serial.read();
 // Put the serial input into the message
 Serial.print(message);
 if (message == '5') {
 Serial.print("test");
 for(pos = 0; pos <= 180; pos += 1) {
 // Goes from 0 degrees to 180 degrees
 // in steps of 1 degree
 myservo.write(pos);
 // Tell servo to go to position in variable 'pos'
 delay(15);
 // Waits 15 ms for the servo to reach the position
 }
 for(pos = 180; pos>=0; pos-=1) {
 // Goes from 180 degrees to 0 degrees
 myservo.write(pos);
 // Tell servo to go to position in variable 'pos'
 delay(15);
 // Waits 15 ms for the servo to reach the position
 }
 }
 }
}

The problem is, when I click my button, nothing happens, but obviously if I remove the if statement, the servo motor code works.

• Omer: Did you make sure that the C# button event is fired, and that the Serial connection is established properly? Also, what happens if you open the Arduino COM terminal and press 5?
• War-sloop: Hum yea , i tested with some console writte and Button work , what do you mean by : press 5?
• Omer: I mean that, in your C# code, you just send "5" to the serial port. As part of the debugging - pin pointing where the problem lays - did you use the Arduino Serial console to send "5" the same way you send it from C#, and made sure it works there? Because if sending "5" from the Serial console in the Arduino IDE doesn't work, the C# way won't work either.
• War-sloop: I follow lot of tutoriel covering this , the code is really similar as mine , but , when I try to use the serial monitor , and I try to fire button event , it say that Com3 is already in use and unauthorized ... 5 is only a message id to call the arduino IF statement ....
• Omer: Yes, I get that 5 is the trigger. What I'm trying to understand is whether that trigger works or not. You cannot use Arduino IDE Serial Monitor while running your C# code since the Arduino COM port can interface only one serial port at a time. Try using the Arduino IDE Serial Monitor after closing the C# serial port and not in parallel to it.

Answer 1

Since you are sending from the Arduino the received serial data back to the C# application (Serial.print(message);), I would advise to check what you receive on the C# side. Register to the DataReceived event of the SerialPort as so:

serialPort1.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

And add an event handler:

private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
 SerialPort port = (SerialPort)sender;
 string data= port.ReadExisting();
 // check here what data you received, if any
}

This way you could confirm that the Arduino gets the data properly from the C# side to begin with. Next step would be to understand if this if statement treats the data properly:

if (message == '5')

But starting from examination of what you get from the C# side will help you decide where exactly is the problem.

• War-sloop: EDIT : NeverMind I missundarstood your post i'm sorry, But i acctualy don't understand your answer, do you mean that I try to send from Arduino to C# because, Me I want to do the opposite...
• Omer: Yes, I mean that you try send from Arduino to C# (you are already doing that) and see what you get. This will help you understand where is the problem.
• War-sloop: Ok so i Will try if i understand to directly send from arduino to c#
• Omer: You are already doing it... the line "Serial.print(message);" sending the message back to the C# code. Just see what you get from the C# side as I explained.
• War-sloop: Hooo yea it was a test code , but I forget to read from C# I'm sorry if I didn't understand but it's because I forget this line ...