How to access USB port via VB.NET?

Question

Hi,

I am currently doing a program to control some device via usb port but i don't know how to interface the usb port using vb.net. anybody can help me with this problem as which namespace I should use? thanks a lot

Answer 1

Hi

It depends on the device that you are trying to communicate with. 

Many USB devices simply emulate COM ports  (S = Serial) and can therefore be communicated with using the System.Net.Sockets.Socket class.  For those that don't, it is usually best to get hold of a generic driver that can handle the conversion for you (http://www.thesycon.com/eng/usbio.shtml)

Hope this helps.

RIchard

Answer 2

According to a Microsoft MVP, VB.NET doesn't have any generic support for USB. You will have to use the Windows API or the API that comes with the USB device. See http://www.thescripts.com/forum/thread336454.html

Ezani

Answer 3

thanks a lot for your info

Answer 4

You can use the wmi to do some of your USB coding
Example to detect if a device is plugged in you would use this code

Imports

 

System.Management

Public

 

Class Form1

 

Dim w As ManagementEventWatcher

 

Private Sub AddUSBHandler()

 

Dim q As WqlEventQuery

 

Dim scope As ManagementScope = New ManagementScope("root\CIMV2")

scope.Options.EnablePrivileges =

True

 

Try

q =

New WqlEventQuery()

q.EventClassName =

"__InstanceOperationEvent"

q.WithinInterval =

New TimeSpan(0, 0, 1)

q.Condition =

"TargetInstance ISA 'Win32_USBControllerdevice'"

w =

New ManagementEventWatcher(scope, q)

 

AddHandler w.EventArrived, AddressOf USBEvent

w.Start()

 

Catch ex As Exception

MessageBox.Show(ex.Message)

 

If Not w Is Nothing Then

w.Stop()

 

End If

 

End Try

 

End Sub

 

 

Public Sub USBEvent(ByVal sender As System.Object, ByVal e As EventArrivedEventArgs)

 

If e.NewEvent.ClassPath.ClassName = "__InstanceCreationEvent" Then

 

Dim s As String

s += e.NewEvent.Properties(

"TargetInstance").Value.Properties("Antecedent").Value.ToString() + ControlChars.CrLf

s += e.NewEvent.Properties(

"TargetInstance").Value.Properties("Dependent").Value.ToString() + ControlChars.CrLf

MsgBox(

"USB inserted, the information is " + ControlChars.CrLf + s)

 

ElseIf e.NewEvent.ClassPath.ClassName = "__InstanceDeletionEvent" Then

 

Dim s As String

s += e.NewEvent.Properties(

"TargetInstance").Value.Properties("Antecedent").Value.ToString() + ControlChars.CrLf

s += e.NewEvent.Properties(

"TargetInstance").Value.Properties("Dependent").Value.ToString() + ControlChars.CrLf

MsgBox(

"USB removed, the information is " + s)

 

Else

MsgBox(e.NewEvent.ClassPath.ClassName)

 

End If

 

End Sub

 

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

AddUSBHandler()

 

End Sub

 

Private Sub Form1_FormClosed(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosedEventArgs) Handles MyBase.FormClosed

 

If Not w Is Nothing Then

w.Stop()

 

End If

 

End Sub

End

 

Class
It may take me a few days but I will be posting code on Http://ess-image.com someplace showing how to talk to usb video control devices such as pan tilt units and controling the camera, so that may help you.
You can also find code sample on codeproject but the ones I found were in C++

I hope this helps you out some

Answer 5

Excalibursoftware thanks for the example.  I tried this and I get "ManagementEventWatcher" is not defined, plus others.  Is there something missing that I haven't put in?  I used the code exactly as you've shown here.

Answer 6

Youmay need to add some Imports statemets at the top of the code.  Fo instance, for ManagementEventWatcher you would need

Imports System.Management

or you can fully specifiy the class in your code - System.Management.ManagementEventWatcher.

Answer 7

Thank you for posting that!!  It is a great help.

Answer 8

Make sure you add the .NET reference for system.management to your project.

Answer 9

can i use this code to controll a device that will act like parallel port.?

i want to use usb port to send data on the device that i will make for it to act as a parallelport.

Answer 10

The device that you will use to act like a parallel port make will provide an interface for the USB port. This interface might be a virtual serial port, or it might be a custom USB interface that uses a device driver. It depends on the device that you are using for this task, the software that comes with that device, or the software that you write for the USB connection on that device.

The fact that you are using this device to act like a parallel port affects the code that runs on the device to manage that parallel port, and it affects the data that you will transfer between the device and the PC. It does not affect the way that the device's USB port communicates with the PC.