Language - Python

Python is an object oriented programming language developed by the Python Software Foundation, is powerful and easy to learn.

Introduction

If this is your first time working with a Phidget, we suggest starting with the Getting Started page for your specific device. This can be found in the user guide for your device. That page will walk you through installing drivers and libraries for your operating system, and will then bring you back here to use Python specifically.

Python is capable of using the complete Phidget API, including events. We also provide example code in Python for all Phidget devices.

Python can be developed with Windows, Mac OS X and Linux. We provide instructions on how to set up your environment/compilers for Visual Studio 2005/2008/2010, Visual Studio 2003, MonoDevelop and the Mono command line compilers.

You can compare Python with our other supported languages.

Quick Downloads

Just need the Python documentation, drivers, libraries, and examples? Here they are:

API Documentation:

• API Manual

Example Code:

• Example Code

Libraries and Drivers:

• Python Library
• 32-bit Windows Drivers Installer
• 64-bit Windows Drivers Installer
• Linux Source
• General Mac OS X Drivers Installer

Getting started with Python

If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:

• Make sure your libraries are properly linked
• Go from source code to a test application as quickly as possible
• Ensure your Phidget is hooked up properly

Instructions are divided up by operating system. Choose:

• Windows 2000 / XP / Vista / 7
• Mac OS X
• Linux (including PhidgetSBC)

Windows(2000/XP/Vista/7)

Description of Library Files

Python programs on Windows depend on the following files, which the installers above put onto your system:

• phidget21.dll contains the actual Phidgets library, which is used at run-time. By default, it is placed in C:\Windows\System32.

You will also need one of the following two files, depending on the .NET framework version you are targeting:

• Phidget21.NET.dll is the Phidgets library for .NET framework 2.0 or higher. Your compiler has to know where this file is. By default, it is placed into C:\Program Files\Phidgets. You can either point your compiler to that location, or copy and link to it in a directory for your project workspace.
• Phidget21.NET1.1.dll is the Phidgets library for .NET framework 1.1. Your compiler has to know where this file is. By default, is is placed into C:\Program Files\Phidgets. You can either point your compiler to that location, or copy and link to it in a directory for your project workspace.

You can optionally install the following files:

• Phidget21.NET.XML provides the IntelliSense in-line documentation for the .NET library in Visual Studio/MonoDevelop. This documentation is also visible in the Object Browser in Visual Studio. By default, it is placed into C:\Program Files\Phidgets.
• Policy.2.1.Phidget21.NET.dll is the policy assembly for Phidget21.NET.dll. Our installer places this file in the Global Assembly Cache(GAC) directory. It directs any programs compiled against version 2.1.0 or higher of Phidget21.NET.dll to use the most recent installed version.

If you do not want to use our installer, you can download the five file files.

Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each compiler below.

Visual Studio 2005/2008/2010

Microsoft makes free versions of Visual Studio available known as Express Editions. The Express editions are suitable for most applications, but are limited in features for more complex applications. Please see Microsoft Visual Studio for more information.

Use Our Examples

Please start by downloading the examples and unpack them into a foler. While these examples were written in Visual Studio 2005 and 2008, Visual Studio 2010 will easily open and upgrade them. To load all projects in Visual Studio, go to File → Open → Project, and open AllExamples/AllExamples.sln or AllExamples/AllExamples_vs2008.sln for Visual Studio 2005 and 2008, respectively.

If you are opening the Phidget examples in Visual Studio 2010, you will need to go through the Visual Studio Conversion Wizard to convert the 2005 or 2008 project.

This will load all of the examples available for C#, and then you can set your main project to be the one that matches your device. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device.

The only thing left to do is to run the examples! Click on Debug → Start Debugging. Please note that the projects, by default try to find the Phidget21.NET.dll in the C:\Program Files\Phidgets. If you have it installed in another location, please change the path to the file's location accordingly. If you are receiving an error message regarding that the namespace Phidgets cannot be found, please re-add the reference to Phidget21.NET.dll. Please see the Write Your Own Code section for details.

Once you have the C# examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your environment to properly link the Phidget C# libraries. To begin:

1. Generate a new Visual C# Windows Applications project with a descriptive name such as PhidgetTest.

2. Add a reference to the .NET Phidgets library.

3. Under the .NET tab, select Phidget21.NET.dll. If you used our installer, these files are installed in C:\Program Files\Phidgets, by default. If it does not appear in this list, then you can browse to the Phidget Framework installation directory and add the file.

4. Then, in your code, you will need to include the Phidget library:

  using Phidgets;
  using Phidgets.Events;

The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

Visual Studio 2003

Use Our Examples

1. Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. If you are not sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. As the examples were written in newer versions of Visual Studio, Visual Studio 2003 is not able to open the examples. Fortunately, you can import the simple examples to a Visual Studio 2003 project. It will be difficult to import the full examples as you will need to recreate the GUI components. In the Use Our Examples section, it will be assumed that the simple examples are used. You will need this example source code to be copied into your C# project later on.

2. Next, a new project will need to be created. Generate a new Visual C# console application project with a descriptive name such as PhidgetTest.

3. Add a reference to the .NET Phidgets library.

4. Under the .NET tab, select Phidget21.NET1.1.dll. If you used our installer, by default, this file is placed in C:\Program Files\Phidgets. If it is in another location, please change the path to the file's location accordingly.

5. To import the simple example program into your project, please: open up Class1.cs.

6. Traverse to the example in Windows Explorer and locate the Program.cs file.

7. Copy and paste the contents from that file into Class1.cs.

8. Comment out the following line as it is not supported in .NET 1.1:

  using System.Collections.Generic;

9. Then, in your code, you will need to include the Phidget library:

  using Phidgets;
  using Phidgets.Events;

10. Now, you can run the example. Click on Debug → Start.

Once you have the C# examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C# libraries. Please see the Use Our Examples section for instructions.

Mono

This section will provide instructions on how to compile using the mcs compiler. Other compilers such as gmcs, smcs, and dmcs all work in the same way. Start by downloading the C# Examples.

Use Our Examples

Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. Please only use the simple examples. The full examples uses Windows Forms, which Mono and the Gtk# toolkit are not completely compatible with. Locate the Program.cs file as this contains the example source code. Copy the file into your working directory, and rename it to example.cs.

To compile and build an executable, run:

mcs /out:example.exe /lib:"C:\Program Files\Phidgets" /r:phidget21.NET.dll example.cs

If you have the Phidget21.NET.dll installed in another location, please change the path to the file's location accordingly.

Afterwards, you will have an executable named example.exe that you can run. Place the Phidget21.NET.dll in the same directory as the executable and type the following to run the program:

mono example.exe

Once you have the C# examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C# libraries. Please see the Use Our Example section for instructions.

In your code, you will need to include the Phidget library:

  using Phidgets;
  using Phidgets.Events;

The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

MonoDevelop

Use Our Examples

Download the examples and unpack them into a folder. Here, you can find example programs for all the devices. These examples were written in Visual Studio 2005 and 2008, but are also compatible with MonoDevelop.

To load all projects in MonoDevelop, go to File → Open, and open AllExamples/AllExamples.sln

This will load all of the examples available for C#, and then you can set your main project to be the one that matches your device. If you aren't sure what the software example for your device is called, check the software object listed in the Getting Started guide for your device. If you are running under the .NET framework, you can use either the full or simple examples. Otherwise, if you are running under the Mono framework, please only use the simple examples. The full examples uses Windows Forms, which is not completely compatible with Mono's Gtk#.

The only thing left to do is to run the examples! Right click the project, and click on Run With and select the target framework. Please note that the projects, by default try to find the Phidget21.NET.dll in the C\Program Files\Phidgets. If you have it installed in another location, please change the path to the file's location accordingly. If you are receiving an error message regarding that the namespace Phidgets cannot be found, please re-add the reference to Phidget21.NET.dll. Please see the Write Your Own Code section for details.

Once you have the C# examples running, we have a teaching section below to help you follow them.

Write Your Own Code

When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget C# libraries. To begin:

1. Create a new C# empty project with a descriptive name such as PhidgetTest.

2. Add a reference to the .NET library.

3. Select Phidget21.NET.dll. If you used our installer, by default, this file is placed in C:\Program Files\Phidgets. If it is in another location, please change the path to the file's location accordingly.

4. Then, in your code, you will need to include the Phidget library:

  using Phidgets;
  using Phidgets.Events;

The project now has access to the Phidget21 function calls and you are ready to begin coding.

The same teaching section which describes the examples also has further resources for programming your Phidget.

Mac OS X

Python has excellent support on Mac OS X.

The first step in using Python on Mac is to install the Phidget libraries. Compile and install them as explained on the getting started guide for your device. Then, the OS - Mac OS X page also describes the different Phidget files, their installed locations, and their roles....

Linux

Python has support on Linux.

The first step in using Python on Linux is to install the Phidget libraries. Compile and install them as explained on the main Linux page. That Linux page also describes the different Phidget files, their installed locations, and their roles.

Follow The Examples

By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want. This teaching section has resources for you to learn from the examples and write your own.

Next, comes our API information. These resources outline the Python Phidget functions:

• Python API (This is the complete set of functions you have available for all Phidgets)
• Device Specific APIs - The one for your Phidget can be found in its user guide.

To learn the details behind opening, configuring, using, and closing your Phidget, try the General Phidget Programming page. That page also describes using the Phidget in an event-driven manner and in a traditional manner, both of which are available in Python.

Example Flow

The Hello World example has this general structure so you can follow along. We also have an in-depth general introduction to writing Phidget code (like open, read data, etc), as well as the Python API for specific syntax:

// ----- Event and Other Functions ----- Create any Language-Specific Functions (exception handling) Create General Attach, Detach, and Error Handling Functions: On attach: Print Hello Message On detach: Print Goodbye Message		In Python, you can name these event functions whatever you like. You will then pass them as function pointers to the Phidget library below in the Main Code section. This hooks them into the actual events when they occur. In the example code, the event functions common to all Phidgets are called things like AttachHandler() and DetachHandler(), etc. Some event functions will be specific to each device, like when a tag is read on an RFID board, or when a sensor value changes on an Interface Kit. Other functions are given in the examples to show you more detail on using your Phidget. For example, DeviceInitialize() will show what needs to be set up for your Phidget before using it.
// ----- Main Code ----- Create Manager Software Object Hook Event Functions created above to Device Open Device Wait for 'Enter' key character input Handle on-going attach and detach events Print Hello and Goodbye messages Exit upon input Close Device Delete Device		Creating a Phidget software object in Python is specific to the Phidget. For a Phidget Spatial, for example, this would involve creating a Spatial object. The examples show how to do this and other API functions. The object provides device specific methods and properties which are available from the API for your specific Phidget.

Common Problems and Solutions/Workarounds

Here you can put various frequent problems and our recommended solutions.