Language - Visual Basic .NET Windows Mono

Visual Basic .NET Development Environments
Windows

Language - Visual Basic .NET Windows with Mono Welcome to using Phidgets with Visual Basic .NET! By using Visual Basic .NET, you will have access to the complete Phidget22 API, including events. Mono is an open-source programming environment that aims to make Microsoft .NET applications available across all operating systems.

Install Phidget Drivers for Windows

Before getting started with the guides below, ensure you have the following components installed on your machine:

1. You will need the Phidgets Windows Drivers

Nuget

The Phidget22.NET library is now available on nuget.org here. Nuget is the recommended way to install and use the .NET library in Mono. The nuget package bundles the C library on Windows, so there are no other prerequisites that need to be installed. The nuget package adds targets for .NET Core and .NET Standard, so it should be usable from almost any .NET environment which also supports the C library.

Use Our Examples

One of the best ways to start programming with Phidgets is to use our example code as a guide. In order to run the examples, you will need to download and install Mono for Windows.

Now that you have Mono installed, download and unpack the HelloWorld example for C#. This example uses the Phidget Manager to list all Phidget channels that can be accessed by your computer:

• HelloWorld example

Note: The HelloWorld example is compatible with Mono because it does not use Windows Forms. All other C# examples use Windows Forms.

Next, copy Phidget22.NET.dll from type the following location:

• C:\Program Files\Phidgets\Phidget22\Phidget22.NET.dll

Place both the HelloWorld example and the Phidget22.NET.dll file in the same location. Your folder should now look something like this:

Open the command prompt at the folder location and enter the following command:

vbnc /r:Phidget22.NET.dll Module1.vb

This will create an executable file called Module1.exe. Type in the following command to run the example:

mono Module1.exe

You should now have the example up and running for your device. Your next step is to look at the Editing the Examples section below for information about the example and important concepts for programming Phidgets. This would be a good time to play around with the device and experiment with some of its functionality.

Editing the Examples

The Visual Basic .Net examples are derived from the Windows Phidget Control Panel, so you'll need to modify a few things to adapt them for your own purposes. To begin with, you can remove the following line:

commandLineData phidgetParameters = open.parseCmdLine(); //get command line parameters

Then, you can modify any line that mentions phidgetParameters by setting it to the desired value instead of using PhidgetParameters object.

For instance:

Try 'set all the values grabbed from command line.  these values have defaults that are set in ExampleUtils.vb, you can check there to see them
    device.Channel = phidgetParameters.Channel 'selects the channel on the device to open
    device.DeviceSerialNumber = phidgetParameters.SerialNumber 'selects the device or hub to open
    device.HubPort = phidgetParameters.HubPort 'selects th eport on the hub to open
    device.IsHubPortDevice = phidgetParameters.isHubPortDevice 'is the device a port on a vint hub?

    If phidgetParameters.isRemote Then 'are we trying to open a remote device?
        device.IsRemote = True
        Net.EnableServerDiscovery(ServerType.Device) 'turn on network scan
        If phidgetParameters.Password <> vbNullString And 
           phidgetParameters.ServerName <> vbNullString Then
           
            Net.SetServerPassword(phidgetParameters.ServerName, phidgetParameters.Password)
        End If
    Else
        device.IsLocal = True
    End If

    device.Open() 'open the device specified by the above parameters
Catch ex As PhidgetException
    errorBox.addMessage("Error opening the device: " + ex.Message)
End Try

Might become:

Try
    device.Channel = 0
    device.DeviceSerialNumber = 370097
    device.HubPort = 0
    device.IsHubPortDevice = True
    device.IsLocal = True

    device.Open()
Catch ex As PhidgetException
    errorBox.addMessage("Error opening the device: " + ex.Message)
End Try

You can then manipulate the rest of the code as your application requires. A more in-depth description of programming with Phidgets will be covered in the next section.

Write Code

By following the instructions for your operating system and compiler above, you now have working examples and a project that is configured. This teaching section will help you understand how the examples were written so you can start writing your own code.

Remember: your main reference for writing VB.NET code will be the Phidget22 API Manual and the example code.

Step One: Create and Address

You will need to declare your Phidget object in your code. For example, we can declare a digital input object like this:

ch = New Phidget22.DigitalInput()

Next, we can address which Phidget we want to connect to by setting parameters such as DeviceSerialNumber.

ch.DeviceSerialNumber = 496911

Although we are not including it on this page, you should include error handling for all Phidget functions. Here is an example of the previous code with error handling:

Try
  ch = New Phidget22.DigitalInput()
  ch.DeviceSerialNumber = 496911
Catch ex As PhidgetException
  errorBox.addMessage("Error initializing: " + ex.Message)
End Try

Step Two: Open and Wait for Attachment

After we have specified which Phidget to connect to, we can open the Phidget object like this:

ch.Open(5000)

To use a Phidget, it must be plugged in (attached). We can handle this by calling Open(timeout), which will block indefinitely until a connection is made, or until the timeout value is exceeded. Simply calling Open does not guarantee you can use the Phidget immediately.

Alternately, you could verify the device is attached by using event driven programming and tracking the attach events.

To use events to handle attachments, we have to modify our code slightly:

Private Sub device_Attach(ByVal sender As Object, ByVal e As Phidget22.Events.AttachEventArgs) Handles ch.Attach
  Console.WriteLine("Phidget Attached!");
End Sub

We recommend using this attach handler to set any initialization parameters for the channel such as DataInterval and ChangeTrigger from within the AttachHandler, so the parameters are set as soon as the device becomes available.

Step Three: Do Things with the Phidget

We recommend the use of event driven programming when working with Phidgets. In a similar way to handling an attach event as described above, we can also add an event handler for a state change event:

Private Sub device_DigitalInputChange(ByVal sender As Object, ByVal e As Phidget22.Events.DigitalInputStateChangeEventArgs) Handles ch.StateChange
  stateText.Text = "State: " + e.State;
End Sub

If you are using multiple Phidgets in your program, check out our page on Using Multiple Phidgets for information on how to properly address them and use them in events.

If events do not suit your needs, you can also poll the device directly for data using code like this:

state= device.State;
stateText.Text = "State: " + e.State;

Important Note: There will be a period of time between the attachment of a Phidget sensor and the availability of the first data from the device. Any attempts to get this data before it is ready will result in an exception. See more information on this on our page for Unknown Values.

Enumerations

Some Phidget devices have functions that deal with specific predefined values called enumerations. Enumerations commonly provide readable names to a set of numbered options.

Enumerations with Phidgets in Visual Basic .NET will take the form of Phidget22.EnumerationType.Enumeration_Name.

For example, specifying a SensorType to use the 1142 for a voltage input would look like:

Phidget22.VoltageSensorType.PN_1142

and specifying a K-Type thermocouple for a temperature sensor would be:

Phidget22.ThermocoupleType.K

The Phidget error code for timing out could be specified as:

Phidget22.ErrorCode.Timeout

Step Four: Close and Delete

At the end of your program, be sure to close and delete your device:

device.Close();

Setting up a New Project

When you are building a project from scratch, or adding Phidget functionality to an exisiting project, you'll need to configure your development environment to properly link the Phidget .NET library.

To include the Phidget .NET library, simply add the following lines to your code:

Imports Phidget22
Imports Phidget22.Events

Success! The project now has access to Phidgets.

Further Reading

Phidget Programming Basics - Here you can find the basic concepts to help you get started with making your own programs that use Phidgets.

Data Interval/Change Trigger - Learn about these two properties that control how much data comes in from your sensors.

Using Multiple Phidgets - It can be difficult to figure out how to use more than one Phidget in your program. This page will guide you through the steps.

Polling vs. Events - Your program can gather data in either a polling-driven or event-driven manner. Learn the difference to determine which is best for your application.

Logging, Exceptions, and Errors - Learn about all the tools you can use to debug your program.

Phidget Network Server - Phidgets can be controlled and communicated with over your network- either wirelessly or over ethernet.