Read A 12 Byte Hex String (RFID Tag ID) Using SerialPort Control?
Apr 23, 2012
I'm trying to make an application that can read a 12 byte hex string from the serial port and display it into a text box, the source is a RFID module that is connected to my USB port using a RS232-USB converter.My first problem was accessing the text box in the datarecieved event due to invalid cross-threaded operation. Upon googling that, I copy/pasted the code I needed to get it work, these are all the cross threading functions.The OpenPort function and Datarecieved event are my own code, the rest I got off google. The application then worked, but I would get an incomplete code, the first swipe I would get all 12 digits, and at every other swipe, the first byte would vanish. Upon some more reading, I decided to make an array, the size of the incoming data (shown in the code below), but now I get the cross-threading error again.I know there's something wrong with the way I'm using the array. This is way beyond my VB knowledge, and I'm in o I'm an electronics engineer and self taught myself a little programming to create some apps for my hardware.Updated code:
Public Class Form3
Dim msg As String
Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
[code]....
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Aug 11, 2011
I want to automatically request the RFID card without having to click the REQUEST button everytime the card touches the RFID reader.
Option Strict Off
Option Explicit On
Imports VB = Microsoft.VisualBasic
[Code].....
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Sep 20, 2011
I'm trying to read a byte array into a string however it's array is filling up from a dll in the following format. [Code] now its decoding the first byte but I think because of the next [0] it's not completing the whole array. This is the code that I'm using:
Radiotext = System.Text.Encoding.ASCII.GetString(szRetRDS)
I did think about writing it into another byte array excluding the [0] but unsure how I would go about this.
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Feb 1, 2010
peoples The User of my application will enter Hexa values in text boxes (00h to FFh). I need to send these values through the serial port, but so that EACH text box with values 00h to FFh ONLY generate ONE transmitted byte, exactly the value placed in the text box.
Just found examples of this application in VB6, using the following command:
MSComm1.Output = (Chr(Val(txtText1.Text)))
In VB2008, you use the component "SerialPort", and one of the methods for transmitting data to the output buffer is "Write". So I did it this way:Dim As Integer ValHex
[Code]...
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Feb 20, 2011
Did anyone already try to read RFID tags but not by reading request?I mean, When some tag is readable can't just the RFID reader detect it?So far this is the code I've been trying to use without success.
Imports System
Imports System.IO.Ports
Public Class Form1
[code]....
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Jul 21, 2010
How would I copy/convert a string containing an ascii representation of hex values in to a byte array containing the actual hex values? For example, I have a variable containing the hex values delimited by spaces (I can change the delimiter):
[Code]...
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Jun 22, 2012
I'm trying to read the binary data from a binary file with the code below but the it's return the value in the byte array. How can i read the binary data from the binary file and then convert the data into string?This is how i create the binary file.
Dim fs As New FileStream(Application.StartupPath & "Agency.dat", FileMode.OpenOrCreate)
Dim bf As New BinaryFormatter()
Call bf.Serialize(fs, GAgency)[code]....
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Mar 27, 2011
I'm trying to get a string from a byte array previously read from memory
i can get the string like this
dim mem as string= ASCIIEncoding.ASCII.GetString(memory) or dim mem as string= UTF8Encoding.UTF8.GetString(memory) but when i try to concatenate this with another string i get a strange result dim result as string = "this is you memory string " & mem & " problem string" no matter what comes after mem in the concatenation it seems like it is not there when in fact it is because when i try this (mem has two chars in it) dim result as string = "this is you memory string " & mem(0) & mem(1) & " problem string" problem string appears so what i assume is that there are some vbCrLf chars in the string after reading (or is it from the conversion?)
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Dec 7, 2009
I have a basic confusion between serial port and network TCP communication to devices.
My colleague uses a vb struct as the nice easy to read way to create a packet to send out via a serial port. Like this basic code sample below of his vb.net serial call followed at bottom by my c# tcp beginsend network call.
Can I use a struct as well to call out for my TCP network beginsend? By looking at the signature of BeginSend(Byte[] as the beginning of the signature for that method call to send data to a connected socket, I don't see myself being able to use a struct.
Public Structure PacketRecord
Dim SourceAddress As Integer
Dim DestinationAddress As Integer
Dim Length As Integer
[CODE].....................
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Apr 6, 2011
Objective: Combine byte arrays, read specific sections, and then cut byte array at specified point.
Private Sub DataArrival(ByRef aBot As xyzSocket, ByRef theData As Byte())
Dim RDLength As Int32
If aBot.ReceivedData Is Nothing Then[code]....
I'm not sure if I have this right to begin with because I can't test it without having it completed.
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Oct 3, 2011
I have one project that I need help writing that I have spent months trying to write with no luck. Anyway so here is my question. I want to write a program that can display a phones filesystems that is connected to my computer by a serial port. I would like to be able to Read/Write files and stuff if possible. I have tried many ways of doing this so this is my last resort.
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Jan 25, 2011
I have a byte array that I convert into a string like so Dim byt As Byte() = New Byte(255) {} s = New String(Encoding.ASCII.GetChars(byte))My question is when I look at the string in a debuger its clearly a normal string but when I compare it to what I know its supposed to be it doesnt equal. So i did a quick check and for some reason its return a string thats the length of 256 characters. So i did a s.trim and it still is 256 characters long.
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Feb 21, 2012
ok i have image that i bind info in it and i want to read the info now from file (FileStream) its workbut i want to do it not from file so i need to use MemoryStreamhere the example that work and how i do it now how i make it work with MemoryStream (with byte = My.Resources or PictureBox1.image)
Using FS As New IO.FileStream(image, IO.FileMode.Open)
FS.Seek(0, IO.SeekOrigin.End)
While Not FS.ReadByte = Asc("|")
[code].....
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Jun 16, 2011
We have been debugging a problem with serial communications with an embedded device on 115200 baud, Even parity, 8 databits and 2 stopbits. The problem: a lot of extra 0x00 are sometimes received from the serialport.
1) We build a real basic sample program that only handles the data exchange. It was completely build according the serial-port-vb.doc from msdn. It was build in vb.net 2010. So this was the most basic setup possible on the PC side. This simple tool clearly shows the datareceived event spitting out extra bytes.
2) We used a scope to look at the hardware bits/levels. No problems / differences seen between good and bad messages. No extra bytes visible that the serialport event send to our programm.
3) We tapped the serial communication and received no wrong data on the tapping system but still on the .net tool. Again the serialport datareceived event gave us many extra 0x00 bytes.
So our only possible conclusion is that there is a problem in the serialport component from .net. My question: Are there any know issues? Can I get in contact with a microsoft engineer?
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Aug 21, 2009
I'm working on application which uses SerialPort Control to send/receive commands to/from microcontroller.
Here is the basic
CODE:
I maybe missing something because the reaction of microcontroller very accidential! I mean, sometime it works from the first click and sometime from the third... I must make a number of clicks until it reacts back!
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Nov 9, 2009
output.gif?I've just upgraded to Visual Studio 2008 and have been given a project and getting gps string from a radio via the serial port. I used a program called "SerialWatcher" and it monitors the data coming in from the radio. It works perfectly. When I tell it the port and settings, click Open, I get consistent output. Here is an example of the data that I got:
<NUL><STX>$PKLDS,124043,A,3337.8562,N,08418.8077,W,000.0,146.5,091109,,00,101,2190,80,00,*1C<CR><LF><ETX><STX>$PKLDS,124104,A,3357.1421,N,08403.0604,W,000.0,000.0,091109,3.0,W00,101,3003,80,00,*61<CR><LF><ETX><STX>$PKLDS,124128,A,3354.1213,N,08414.3434,W,000.1,274.3,091109,4.9,W00,101,2576,80,00,*64<CR><LF><ETX>
[code].....
The little icon symbol before the dollar sign is actually two symbols which I think are the <stx> and <etx>. I'm including a screenshot to show what they actually look like. From the output my program created all I would need is actually the last line. I can't really check for "length" because some data received by the radio will be half that length (or more than half). But there should always be a start and end (regardless of what is in the middle) I would think.
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Feb 17, 2009
I am using VB2008 SerialPort to communicate with a device. My problem is, using RTS handshake I am missing the first 50 or 60 chars, after that everything is intact. I tried to change the buffer size - Has no effect, used standard, bigger, smaller and no change.
The device timing says when it sends CTS signal, it will start listening 100ms after that. I have no clue how to delay the write to test this. Should I first write to the buffer then write to the port after a a 100ms timer event?
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Mar 2, 2012
i am receiving data from serial port and i update a richtextbox in a MDI Form with the control.invoke method
(Code in SerialPort.DataReceived Event)
If myTerminal.Visible Then
myTerminal.MyRichTextBox1.Invoke(New MethodInvoker(Sub()
myTerminal.MyRichTextBox1.AppendText(dataLine & vbCrLf)
End Sub))
End If
But as a mdi form it has the ability to close and reopen. So when the serialport is sending data to richtextbox and the user click the close button and the form gets disposed. Then the error "Invoke or BeginInvoke cannot be called on a control until the window handle has been created."...
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Aug 27, 2009
i am developing an application which needs to connect to a weighjng scale throug rs 232 and capture the output. after inserting the record however the pc needs to send the tare command to the weighing scale in order to set the scale to zero. now he tare character as far as i guess ia T i sent the command like this
serialport1.write(chr(27) & "T" & chr(13) & chr(10))
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Sep 20, 2009
How do I read a raw byte array from any file, and write that byte array back into a new file?
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Apr 26, 2010
I have a client(VB.Net) that receives a packet from the server(Java), and for a while I struggled with some really weird packets that didn't make any sense, eventually took a look at the Java servers source and saw packet structures like this...
[code]...
and so I came across the term of bit-masking. After a few failed attempts and unsatisfying google searches later, here we are.In short, I need to read a byte array bit by bit.
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Feb 9, 2011
I am trying to achieve a drag and drop of outlook emails to my vb app. I found this thread which is very helpful
[url]...
the op shows how to get the FileName returned as well as a byte array which contains other data about the email message.
How can I read the byte array and get out the other information about the email message?
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Jun 30, 2011
read data from a text file with SERIALPORT while using "StringReader.ReadLine"?
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Aug 13, 2010
I am writing a small app that is retrieving data from a device connected to a virtual com-port. I connect without problems to the device using the settings 9600-8-N-1.
I need to send the command <esc>MS , the device then sends back the data to a computer. I have tried this using Hyperterminal with success. I also did this with Excel and VBA. I used the MSComm32 Active X control:
MSComm1.Output = Chr$(27) + "M" + "S" + Chr$(13)
Msgbox(MSComm1.Input)
This made the data from the device pop up in a messagebox. I am writing a winforms app in vb.net, using VS2005. I have a form, on which I have a Placed a SerialPort control, named sp. My sample code is as follows:
Private Sub Form1_Load(ByVal
sender As System.Object,
ByVal e
[CODE]...
This returns the error message "Error: expecting a command". I have done som tests in HyperTerminal, and have concluded with:
-If I dont send <esc>, I get error "Expecting a command"
-If I send wrong command (ie MD instead of MS) i get error "Bad command"
Based on this, I suspect that I don't pass the escape character correctly to my device. So I wonder how to do this?
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Aug 7, 2010
Why does C# define Byte+Byte=Int32 instead of Byte+Byte=Byte like VB?
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Feb 20, 2012
I try to load image byte to memory and read it in memory (not from file - string)
with FileStream i do it like FileStream(image, IO.FileMode.Open) image = string of file path
so i want to do it with MemoryStream(image) image = image byte
i try many things but still cant get it [code]...
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Apr 9, 2012
1.txt content:
1224hafhal2948102
My code:
Dim data() As Byte = System.IO.File.ReadAllBytes("c:1.txt")
label1.text=data(1)
How do read first byte,last byte(get the value) from my text file? From my file, i want read the first char "1" and last char "2" through read byte method and show in label.
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Apr 13, 2012
i m using readallbyte method to read my log file. How to get first five bytes in every lines to do the comparison?
Dim data() As Byte = System.IO.File.ReadAllBytes("c:1.txt") 'read log file in bytes
Dim lines() As String = System.IO.File.ReadAllLines("c:1.txt") 'read log file in lines
Let's say:
For i=0 to 100
If lines(i).startwith("212330") Then
'code
End If
Next
The value 22330 is read from the file in byte. But i not sure whether can find the byte value by using readalllines method.
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Mar 15, 2010
Is there any special way of reading a pdf file into a byte array? The reason I ask...I want to fax a pdf file using faxDocument and FaxServer. My current code is working fine for everything else. Now I know that in the documention it says it should not work for pdf. But I can get some pdfs to send and some do not. When I fax a pdf through windows, it works. [code]....
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Mar 7, 2010
Some binary files have application variables at the end if you open it with a text editor you can see these variables. Now when I read these files into the processor memory the program does not work properly, however if I read a file without this it works fine. So how can I read a byte[] array to EOF so that when I pass that byte array into win32 api create-process it will create the process without corrupting the program?
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