Good afternoon everyone,
I'm experimenting with serial communication between c# and arduino.
To understand how the comms work with regards to sending numbers (I know, there's alot being discussed already but bear with me) I want to send the value of a trackbar to the arduino, and then translate this number in movement of a servo.
If I understand correctly, integers can't be sent directly but have to be converted into bytes first.
So for this I would convert the numeric value of the trackbar into a byte array
in C# :
byte[] Numbers;
Numbers = BitConverter.GetBytes(trackBar1.Value);
Via serial communication I would send the value
port.Write(Numbers, 0, 1);
And this is where I'm going wrong I think
The trackbar value goes from 0 to 255, so I guess I'd need to know the bytes that equal 0 to 255 to be able to adjust the last number (in my example '1') to get the correct number after translation in Arduino?
As for Arduino, I would 'translate' the bytes as follows:
int IncomingValue = Serial.parseInt();
And then I'd like to use the IncomingValue for my servo.
My question is what I'm doing incorrectly.
thanks
For those interested in tinkering with c# to arduino serial communication (just desribing the issue I had) and sending a value of a trackbar to use in arduino:
make yourself a form project and name it whatever you like.
Then create a trackbar. I will create a trackbar with a minimum value of 0 and a maximum of 255 as follows:
trackbar1.Minimum = 0;
trackbar1.Maximum = 255;
trackBar1.TickFrequency = 10; // this will set ticks every 10 units.
Now we can setup the actual communication between c# and arduino. I'll start with c#.
Opening a port:
port = new SerialPort("COM5", 9600); //Set your Arduino COM port and baud rate
port.Open();
Now we also need to create an event to close the port when the program shuts:
void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
if (port != null && port.IsOpen)
{
port.Close();
}
}
Now we have set up the port, but we still need data to send. In our example we told we were going to send the value of the trackbar. To do this, click on your trackbar and find the trackBar1_Scroll event and double click it.
This basically creates the event of scrolling the trackbar and now we have to describe in this event what we want to happen.
We want to send the data of the trackbar via serial. The trackbar value is retrieved as follows:
trackbar1.value
Now we know how to retrieve the value, we have to look at the options of sending it, there's 3 options using port.write(), we'll use this later:
-Write(String)
-Write(Byte[], Int32, Int32)
-Write(Char[], Int32, Int32)
but as I'm working with an int, I found that the second one was the one I needed.
As you can see we need a Byte array to be able to send this, so we will cast our trackbar data into a byte array by using BitConverter and declaring a byte array called Numbers:
byte[] Numbers = BitConverter.GetBytes(trackBar1.Value);
Now we have every element we need:
The port which has been opened. We also described when to close it.
The trackbar and its data to send.
The data of the trackbar 'packaged' the correct way to be able to send it.
the only thing we didn't do is describe the scroll event, but now we have the correct data format, we can:
private void trackBar1_Scroll(object sender, EventArgs e)
{
byte[] Numbers = BitConverter.GetBytes(trackBar1.Value);
port.Write(Numbers, 0, 1);
}
so in c# our code will look like this:
public Form1()
{
InitializeComponent();
trackBar1.Minimum = 0;
trackBar1.Maximum = 255;
trackBar1.TickFrequency = 10;
port = new SerialPort("COM5", 9600);//Set your board COM
port.Open();
this.FormClosed += new FormClosedEventHandler(Form1_FormClosed);
}
void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
if (port != null && port.IsOpen)
{
port.Close();
}
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
byte[] Numbers = BitConverter.GetBytes(trackBar1.Value);
port.Write(Numbers, 0, 1);
}
As for arduino, all we need to do is:
A] Start our serial
B] Read the incoming data
#include <LiquidCrystal.h> // include the LCD library
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //define the LCD display
int Number; //define the number int (the one we'll store our received trackbar value in)
void setup()
{
Serial.begin(9600); //A] Start our serial
}
void loop()
{
lcd.setCursor(0, 0); // Set the LCD cursor at the top left corner
if (Serial.available() > 0 ) { //B] Read the incoming data
nummer = Serial.read(); //
lcd.print(nummer); //
} //
else {}; //
}
I used an LCD to read the data as I couldn't figure out a way to open the serial monitor with the serial communication between c# and arduino happening.
that's why I included an LCD.
I feel explaining this is beyond the scope of this little issue I had.
I hope this helps other beginners like me in the future.
thanks to those who were helpful!
Related
I'm new to the Arduino and serial communication, and I haven't coded in a while, but I'm trying to do what I think should be fairly simple, and have been having plenty of trouble. What I'd like to do is to create a simple GUI on Windows Forms and control a Arduino. I keep seeming to run into different problems every new session.
What I've been trying to do is to create a simple GUI that can toggle an LED on and off, and then to use NumericUpDown to toggle it blinking. Previously, I could get the numericUpDown to toggle values but nothing happens, now if I try and toggle, it tells me the port is closed. I've been trying different port communication methods. Since the Form is saying my port is closed, I cannot test to see if what I've written works. Please ignore the commented code as I'm still trying different things.
When I try to call the blink function, it hasn't blinked properly inside a if statement compared to if I kept it in the loop. I'm not sure how and where to send the value from the Winform to the Arduino.
Is Winform much different than using serial monitor commands?
EDIT1: I stepped away from my computer and now when I run the Windows Form, it shows no errors but The program has exited with code 0 (0x0). I've had the timer and haven't really messed with it yet but it wasn't telling me this error earlier and was running the form fine.
My Arduino Code:
// Define Function Prototypes that use User Types below here or use a .h file
int dorun;
int Blinks;
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(9600);
getBlinks();
}
// the loop function runs over and over again forever
void loop()
{
if (Serial.available() > 0)
/*
{
byte Blinktimes = Serial.readBytes[];
}
*/
{
String serialInput = Serial.readString();
//Toggle LED
if (serialInput == "On")
{
digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN)); //I have this just to see that the LED is staying on and off, and will need to change things.
for (int x = 1; x = Blinks; x++)
{
blink();
}
}
else
{
digitalWrite(LED_BUILTIN, LOW); // turn the LED on (LOW is the voltage level)
}
Serial.flush(); //Clear Serial
}
/*
digitalWrite(LED_BUILTIN, HIGH);
if ((Serial.available()))
{
int dorun = Serial.read();
if (dorun = 1)
{
blink();
}
else
{
digitalWrite(LED_BUILTIN, LOW);
}
}
*/
/*turnon();
if (dorun == 1)
{
blink();
}
else
{
digitalWrite(LED_BUILTIN, LOW);
}
*/
}
void getBlinks()
{
byte message[3];
if (Serial.available())
{
Serial.readBytes(message, 3);
Blinks = message[3];
}
}
void blink()
{
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the
voltage level)
delay(250); // wait for a second
digitalWrite(LED_BUILTIN, LOW); //!digitalRead(LED_BUILTIN); // turn the LED off by making the voltage LOW
delay(1000);
}
void turnon()
{
if (Serial.available()> 0)
{
String run = Serial.readString();
if (run == "Run")
{
dorun == 1;
}
if (run == "Off")
{
dorun == 0;
}
}
}
My Windows Form Code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO.Ports;
namespace WindowsFormsApp9
{
public partial class Form1 : Form
{
SerialPort serial; // create serial port
/*
* public class Port
{
public string Name { get; set; }
public int Value { get; set; }
public Port(string n, int i)
{
Name = n;
Value = i;
}
}
*/
SerialPort port;
string[] availablePorts = SerialPort.GetPortNames();
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
port.Write("On");
port.Close();
}
private void button2_Click(object sender, EventArgs e)
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
port.Write("Off");
port.Close();
}
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
UpdateBlink();
}
void UpdateBlink()
{
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
port.Open();
const byte messageType = 2;
byte Blinkcount = (byte)numericUpDown1.Value;
byte[] serialBlink = { messageType, Blinkcount };
serialPort1.Write(serialBlink, 0, serialBlink.Length);
port.Close();
}
private void timer1_Tick(object sender, EventArgs e)
{
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
}
I've been checking out these links:
Click here How I toggle the LED
Click here How to return an int since NumericUpDown returns a decimal
Click [here] (https://www.instructables.com/id/Arduino-Visual-Studio-Serial-Communication/) Arduino Visual Studio Serial communication timer things
Click [here] (https://www.instructables.com/id/Communication-From-a-WinForms-to-a-TinyDuino/) instructions about Winforms to TinyDuino, They should use similar commands as the Arduino right?
So I decided to do a slight overhaul. Instead of trying to deal with sending multiple different types of inputs(String and int) I have decided to just change everything into a byte array and then send it all at once.
Regarding 1. I was really just wondering if it'd be alright to create a function to return a value rather than just building the code in a void function. So I tried it and it worked, hence the change. From what I understood and saw that your protected override bool ProcessCmdKey, basically you wanted to see if the key was an arrow key. If it was return true. So what I did was basically if it's one of the selected colors, return a value corresponding to the color.
I was just hoping you could either help me understand the Serial and COM port connection or if you had a link for more explanation. Earlier when I was trying to send a string(On/Off) and then send a numeric(byte/int) to set a number of blink times, I couldn't figure out if the COM port is kind of like a singular channel. If I'm sending a string from the Windows Form, could I send out a int/byte in the same channel? Now that everything is of one keyword (byte) I can just create a byte array and figure out the communication between the Windows Form and Arduino. I'm a little confused about the underlying Serial aspect. When I saw your code I started to think a little differently.
In your code, if I'm understanding it properly, it seems that MyVCOM is how to communicate back and forth, just like port.Write. I believe it's singular as it's basically like the old telephone line, if I'm on a call, and you call try to call me, your call is blocked since my line is already being used.
So in your ConnReset, you want to make sure the COM's aren't open so you can set up communication. So your ConReset will clear the line if it's open already. What I'm confused about is the else part. If your port isn't open, open COM+PortNumber, so basically open the channel so you can communicate, but you declared port number to be 8, so shouldn't you just use:
MyVCOM.PortName = "COM8";
Where does the user select which COM? All of the communication is being done on COM8 isn't it? Or does is that part all part of a built in library? I believe all I need to do now is to send my byte array to my Arduino and then work on the Back End to take the data the Windows Form is sending.
public int Colorselection(string label3, int color) //Toggle a pin
{
if (label3 == "Red")
{
color = 6;
}
else if (label3 == "Green")
{
color = 5;
}
else if (label3 == "Blue")
{
color = 3;
}
return color;
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
String label4 = LEDColor.SelectedItem.ToString(); //Generate A string of selected Color
int xled = Colorselection(label4, color); //Toggle the string into an int
LEDLabel.Text = xled.ToString(); //Generate a string from the int
}
private void Run_Click(object sender, EventArgs e) //Generate byte to send instead of sending strings and int/byte
{
byte RGBLED = Convert.ToByte(color);
byte BlinkNum = Convert.ToByte(number1.Value);
byte BlinkDur = Convert.ToByte(number2.Value);
byte[] array2 = new byte[] { RGBLED, BlinkNum, BlinkDur };
port = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
/*
port.Open();
port.Write(array2, 0, 2);
port.Close();
*/
}
Your WinForms application assumes that your Arduino is connected to COM3. Do you know if that's actually the case, or is that sample code that you just copy and pasted? (Check the Windows Device Manager under COM ports to see what ports are available, then unplug/plug your device to see which port it's being mapped to)
Besides that, have you tried debugging your Arduino code on target to see what, if anything, is actually being received?
From the MS documentation, it's not clear how the SerialPort.Write command works exactly in terms of synchronization, so it may not be a great idea to close the port immediately after sending your command. Unfortunately, since I'm not in possession of an Arduino I can't test your code. But I did create a WinForms GUI to accomplish essentially the same task (and more that you probably don't need) several years ago that I've since posted to github (https://github.com/mbhul/RoboCOM). Let me know if that helps, otherwise please tell us more about your development environment.
I'm trying to create a Serial Communication tool on MSVS using C#. it communicates with the Photon MCU and a bluetooth dongle.
When the "start" button is pressed, the UI sends a "1" to the Photon which it first sends the current time stamp and starts streaming data from the function generator. When the "stop" button is pressed, It first sends 10 "2"s (due to the timer issue on the photon's end) which the when the Photon receives, it stops transmitting the function generator's data. Then it sleeps for a second and sends a "3" which it sends another current time stamp. Then the UI discards data in the InBuffer and stops reading data.
connectBT is connected with the start button and the disconnectBT is connected with the stop button.
This is the code that I have right now:
SerialPort serial = new SerialPort();
string recieved_data;
int startBuffer = 0;
private void connectBT(object sender, RoutedEventArgs e)
{
startBuffer++; // keep track of BT open counter
if (serial.IsOpen) Debug.WriteLine("BT Open");
// first time BT is open and BT is not open
if (!serial.IsOpen)
{
if (startBuffer == 1)
{
// COM port properties
serial.PortName = "COM7";
serial.BaudRate = 38400;
serial.Handshake = Handshake.None;
serial.Parity = Parity.None;
serial.DataBits = 8;
serial.StopBits = StopBits.One;
serial.ReadTimeout = 200;
serial.WriteTimeout = 50;
serial.Open();
}
startButton.Content = "Recording";
Send_Data("1"); // tell Photon to start sending data
serial.DiscardInBuffer(); // discard whatever is in inbuffer
serial.DataReceived += new SerialDataReceivedEventHandler(Recieve); // start receiving data
}
// after BT has been opened and start button has been pressed again
else if (serial.IsOpen && startBuffer > 1)
{
startButton.Content = "Recording";
Send_Data("1");
serial.DiscardInBuffer();
serial.DataReceived += new SerialDataReceivedEventHandler(Recieve);
}
}
// stop button is pressed
private void disconnectBT(object sender, RoutedEventArgs e)
{
// send "2" ten times to tell photon to stop transmitting function generator data
int i = 0;
while (i < 10)
{
Send_Data("2");
Thread.Sleep(1);
i++;
}
Thread.Sleep(1000);
Send_Data("3"); // send a 3 to tell photon to send the last time stamp
Thread.Sleep(1000);
serial.DiscardInBuffer(); // discard in buffer
serial.DataReceived -= Recieve; // stop receiving data
//serial.Close(); // close BT
startButton.Content = "Start";
}
private void Recieve(object sender, SerialDataReceivedEventArgs e)
{
recieved_data = serial.ReadLine();
Debug.WriteLine(recieved_data);
}
I'm running into an issue where when I press the "stop" button, the last chunk of data that was sent from the bluetooth is lost. I never receive the last time stamp that I'm supposed to have received when the stop button is pressed. According to our math, we're supposed to be receiving 500 points per second (500Hz) but I only receive about 100 of them.
My theory is that the UI is receiving data at a slower (or a delayed) rate and the serial.DiscardInBuffer discard the received data even before that the data can be printed to the Debug output. I know for a fact that all the data between the first and last I receive are all there because of counter values associated with the data packets. Basically if I were to receive 1~500 data points, I only receive 1~100. I've also tried it with just termite with sending 1,2, and 3 as the UI is supposed to be and I get all the data as I need them. I don't close BT on purpose.
What can I do to prevent this data loss? What am I doing wrong in my code that I shouldn't be doing or be doing for the correct bluetooth protocol? This is my first time writing bluetooth code so I'm fairly unfamiliar with it.
Not sure if that's the cause of your problem, but your Receive has a very big pitfall.
You only read one line per Receive event, and on one event there can be more than one line to read, then they are being accumulated and discarded at the end.
ReadLine is meant to be used in a synchronous way like an stream where you read one line, process it then you write, not to be used with the DataReceived event.
You have two options: spin a new thread in a continuous loop reading with serial.ReadLine() (it will block until a new line is available) or the better approach, read the serial buffer on each Receive event.
To do it like that you can do smething like this:
List<byte> tmpBuffer = new List<byte>();
static byte newLineB = Encoding.ASCII.GetBytes("\n")[0];
void Receive(object sender, SerialDataReceivedEventArgs e)
{
lock (tmpBuffer)
{
while (serial.BytesToRead > 0)
{
byte[] segment = new byte[serial.BytesToRead];
serial.Read(segment, 0, segment.Length);
tmpBuffer.AddRange(segment);
ProcessBuffer();
}
}
}
private void ProcessBuffer()
{
int index = 0;
while ((index = tmpBuffer.IndexOf(newLineB)) > -1)
{
string line = Encoding.ASCII.GetString(tmpBuffer.Take(index + 1).ToArray());
//Do whatever you need to do with the line data
Debug.WriteLine(line);
tmpBuffer.RemoveRange(0, index + 1);
}
}
As you can see, the received data is being stored on a temporal list used as a buffer (yes, an array and using Buffer functions would be faster, but for small messages and for simplicity a list is enough for most cases), then the received data is added to the buffer and when there are no more bytes left the list is processed in search of string lines.
Also note the read is in a loop, I have run in cases where there were data received while the function was being executed and no receive event was fired, so the better for this is to create a loop to read while there is still data.
Thank you all for your response, they all helped me reaching the solution for my issue, but in the end what fixed it was delaying the time between sending the "3" and discarding my inBuffer and closing the Receive connection.
async Task DelayBT()
{
await Task.Delay(100);
}
Thread.Sleep() didn't work because of its nature disabling all action within the thread (which I still needed) so this method worked like a charm. I just called await DelayBT where I needed the delay.
Hope this helps anyone running into the same issue as me.
I know this is answered question however I want to know hardware required and how to setup.
I am trying to build a take-out's delivery system wherein users call and their phone number gets captured on a WINFORM.
I googled and it says I need to use TAPI API. That's fine but do I need to connect anything to the PC or will just using TAPI work?
This Link explains it in VB.net. I am looking for it in c#.net.
I have also gone through the links provided here.
But nowhere does it explain the setup. So please help.
First thing
See if your hardware supports caller ID
Add the serial port control, set it to whatever comm port your modem is on and watch for the CALLER ID number, then react
To see if your modem supports Caller ID open a serial port terminal (I like putty) and set it to the com port of your modem then call the phone number attached to that that modem, you should see something like RING 5555555555 (where 5555555555 is the phone number of the person calling you)
You may have to turn caller id on for that modem (if so)
1) Open the "Phone And Modem Options" control panel
2) Click the "Modems" tab
3) Select your modem in the list (if it is not already selected)
4) Click the "Properties" button
5) Click the "Advanced" tab
6) Type "#CID=1" into the "Extra initialization commands" edit box
Note: replace "#CID=1" with the command to enable caller id on your modem
Do not include the "AT" part of the command
Do not include the quotes
7) Click OK
8) Click OK
9) restart the computer
Here is some code for interacting with a serial port in c# (incase you need that)
public SerialPort sp;
string dataReceived = string.Empty;
private delegate void SetTextDeleg(string text);
private void FormLoad()
{
sp = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
this.sp.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived);
sp.Open();
}
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
Thread.Sleep(500);
string x = sp.ReadLine(); // will read to the first carriage return
this.BeginInvoke(new SetTextDeleg(si_DataReceived), new object[] { x });
}
catch
{ }
}
private void si_DataReceived(string data)
{
dataReceived = data.Trim();
// Do whatever with the data that is coming in.
}
Also I just searched amazon for "Caller ID Modem" and there seem to be alot for between 10 and 20 dollars (US) that support this exact use. I would recommend the Trendnet TFM-561U
If you are using a phone and fax modem, just plug-in your telephone line into the modem.
Next on your windows form drag-n-drop a SerialPort control and initialize it.
this.serialPort1.PortName = "COM3";
this.serialPort1.BaudRate = 9600;
this.serialPort1.DataBits = 8;
this.serialPort1.RtsEnable = true;
this.serialPort1.DataReceived += serialPort1_DataReceived;
this.serialPort1.Open();
Pass the following command to modem in order to activate Caller-ID
this.serialPort1.WriteLine("AT#cid=1" + System.Environment.NewLine);
Handle its DataReceived event and display the received data
void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
richTextBox1.Text += this.serialPort1.ReadLine();
}
Output:
RING //On 1st Ring
DATE = xxxxx //On 2nd Ring
TIME = xxxx
NMBR = xxxxxxxxx
RING //On 3rd Ring
RING //On 4th Ring
P.S. If the telephone line sends DTMF tones as Caller-ID then you need DTMF to FSK converter to detect the number, or else you will receive the rings but not the number.
i'm trying recieving data samplings trough serialport and plot a chart with this sampling vs time. the data is attatched to a resizable array and treated to correct some errors detactable by some marked bytes. i get recieve the data properly till 25 seconds. After this time, the data is unreadable and uncorrectable. i supected any configuration of buffersize of the serial port but any change does not solve this problem. and i don't find any configuration in the chart that could affect the behavior after certain point. my code to correct any error is limited and just works with litle bytes lost, not larger blocks. but what make confused is this constant lost axactly at 25s, that make me suspect of any colision and lost of larger blocks in serialport.
private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
if (serialPort1.BytesToRead != 0)
{
try
{
for (uint i0 = 0; i0 <= _In_Buffer.Length | serialPort1.BytesToRead != 0; i0++)
{
Array.Resize(ref _In_Buffer, (_In_Buffer.Length + 1));
_In_Buffer[i0] = (byte)serialPort1.ReadByte();
}
}
catch
{
}
}
i'm new in c#, how you can see by the code. the baudrate is 115200 and redbuffersize 1048576. if someone can an idea what occurs to this behavior...
thx all
Life status of device connected via serial port.
Hello everyone.
How can I check if the device responds to the request? I'm googling this for couple days and tried lot of solutions also from SO, but nothing gave me results that I've expected. After lot of tries I'm in point described below. I think I'm very close but now I need little help, so thanks for every answer in advance.
The current situation
What am I doing right now is very simple. First of all I'm opening serial port serialPort.Open() at very beggining of app (data is receiving almost all the application running time).
As this is just an example in my form is only one label called labelStatus and labelStatus.Text = "Not connected"
Next I'm adding a timer and it's tick method, that contains execute of serialPort.Write(). Timer Interval is set to 100 if that matters.
private void timer_Tick(object sender, EventArgs e)
{
if (serialPort.IsOpen)
{
serialPort.WriteLine("r"); //I'm sending "r" message and device send data back
}
}
Next step is create DataReceived event like below (very simplified version, in my app received data is parsing to floats and storing in array, but it's just to show the problem)
private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
string someVariable = serialPort.ReadLine();
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Connected"));
//If i received something that means the device is plugged in and connection is correct (still very simplified)
}
One last thing is create ErrorReceived method.
private void serialPort_ErrorReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Not connected"));
}
Untill now everything works brilliant. Sending data works. DataReceived event is executig each 100 miliseconds when data is send. My data is received properly with no problems. When I start application labelStatus text is "Not connected" (device cable is not plugged in). When I plugged in device labelStatus text changing to "Connected". But now when I plugged of cable ErrorReceived event is not executing and labelStatus text is still "Connected". So as I've asked before: How can I check is device still connected to computer? (Or maybe: how to execute ErrorReceived event, when data is not receiving?).
Note: Serial port ReadTimeout is set to 300 miliseconds.
What have I tried
I've tried lot of things but this one in my head seems to should work but doesn't.
I've modified DataReceived event and I've put serialPort.ReadLine() into try/catch block with TimeoutException where I've tried to manually execute ErrorReceived method like below
private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
try
{
string someVariable = serialPort.ReadLine();
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Connected"));
//If i received something that means the device is plugged in and connection is correct (still very simplified)
}
catch (TimeoutException)
{
serialPort_ErrorReceived(null, null);
}
}
I was hoping that will work like I want.
BTW. Sorry for my English. It's not perfect, but I do my best. Cheers!
Listen to the WM_DEVICECHANGE event that will be fired when a device is removed or inserted.
Here is an example of a implementation and some more information:
Detect serial port insertion/removal
http://www.codemiles.com/download/file.php?id=719 (USB Sample)
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363480(v=vs.85).aspx
This is solution in my case
Regarding to Martjin's answer i need to further explain my situation. First of all I want to say that I'm not installing any hardware into my computer, so in my opinion WM_DEVICECHANGE event was not what i need (but of course thanks for information, I've learned something new). Application is reading data from scale. Scale after plug into com port is not sending any data and actually there's no communication between it and computer at all. The only way to read data is to send request to scale, so I have to rely on that.
First try
The plan:
Add two static int fields (flags) checkOld and checkNew,
increment checkNew in DataReceived, check in timer Tick method
is checkOld is equal to checkNew. If true that means checkNew
was not increment, and that means DataReceived was not executed.
`
private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
checkNew++;
string someVariable = serialPort.ReadLine();
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Connected"));
//If i received something that means the device is plugged in and connection is correct (still very simplified)
}
private void timer_Tick(object sender, EventArgs e)
{
if (serialPort.IsOpen)
{
serialPort.WriteLine("r"); //I'm sending "r" message and device send data back
}
if (checkOld == checkNew)
{
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Not connected"));
}
}
`
The plan was good but when I've tested it result was not even good. What happened? Actually device status was blinking connected-not connected-connected-not connected etc. I've wrote some data to output and get answer. The timer was looping so fast that DataReceived event could not always increment checkNew value.
Final solution
Based on what I had at the moment I've decided to add some little changes. Instead of comparing two integers values try to collect couple last values ad check if all were the sem or not.
The plan:
Add three static fields: first six elements array of integers
statusArray, second integer index with value equals to 6 (last
element of array + 1), third integer checkNew,
increment checkNew in
DataReceived event,
in timer Tick event fill array to index,
decrement index value untill whole array is filled, and if index == 0 reset index value to
6,
and last check if last six values of checkNew, stored in
statusArray are the same. If true that means DataReceived did not
executed six times in a row, and now I can be sure that connection is
lost.
`
static int index = 6;
static int checkNew = 0;
static int[] statusArray = {0,0,0,0,0,0};
private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
checkNew++;
string someVariable = serialPort.ReadLine();
labelStatus.Invoke((MethodInvoker)(() => labelStatus.Text = "Connected"));
//If i received something that means the device is plugged in and connection is correct (still very simplified)
}
private void timer_Tick(object sender, EventArgs e)
{
if (serialPort.IsOpen)
{
serialPort.WriteLine("r"); //I'm sending "r" message and device send data back
}
if (index == 0)
index = 6;
index--;
int value = statusArray[index] = checkNew;
}
`