OS - Linux

From Phidgets Support
Revision as of 20:05, 8 December 2011 by Cora (talk | contribs) (→‎Checking)

Phidgets can run on Linux directly using USB, or remotely over a network using the Phidget Webservice.

You need kernel version 2.6 or later.

Getting Started (Libraries and Drivers)

Linux does not have a graphical user interface to check your Phidget, but it does have a complete API for many languages.

For any language, you will need the basic Phidget Libraries for Linux:

Installing

To install the libraries, follow these steps:

  1. Download libusb-0.1 and its development libraries
    • Try apt-cache search libusb in a terminal to find current packages
    • Or install from source, which includes the libusb development libraries
  2. Unpack and install the Phidget Libraries for Linux (download above)
    • From the main libraries directory, run:
      ./configure
      make
      sudo make install
    • This will compile phidget21.h and place the library into your gcc path

Checking

To confirm that the libraries were installed correctly, you can use the Phidget C Examples:

Although the libraries are written in C, the libraries for Python, Java, and most other Phidget-supported languages depend on them.

The easiest way to confirm that the libraries got compiled correctly and installed in the right place will be to compile and run the HelloWorld C example. This does not involve writing any C code, but would involve compiling the example and running it.

If you feel more comfortable running the HelloWorld example for your specific language, you can skip below and pick your language, but keep in mind that any problems could be with the C libraries and not necessarily with your language.

To compile and run the basic C example for checking your installation, copy and run these lines in a terminal, in the directory where you saved and unpacked the C examples:

  1. Unpack the Phidget C Examples (download above)
  2. Compile and run the HelloWorld.c example:

     gcc HelloWorld.c -o HelloWorld -lphidget21
     sudo ./HelloWorld

(The sudo is needed for USB access for now)

The -lphidget21 will look in the standard library location for your Linux distribution (usually /usr/lib/) for the Phidget 21 library file. Generally, libraries to be linked on Linux through gcc have a naming convention. For example, -lphidget21 looks for the libphidget21.a and libphidget21.so in the library location.

The HelloWorld program will simply print out basic information for any device you plug in, and print a message upon unplugging the device. For example, starting the program, plugging in an Interface Kit Phidget, unplugging the Interface Kit, and pressing Enter displays:

   $ sudo ./HelloWorld 
   
   Opening...
   Press Enter to end

   Hello to Device Phidget InterfaceKit 8/8/8, Serial Number: 37299
   Goodbye Device Phidget InterfaceKit 8/8/8, Serial Number: 37299

   Closing...

Programming Languages

Now that you have the basic libraries installed, you can pick your language and begin programming!

If you are not using the webservice (discussed below) to control a Phidget over a network, your next step will be to delve into the use of your specific language. Each page has its own set of specific libraries, code examples, and setup instructions.

On Linux, we recommend the following languages:

You can also use these languages, but they do not support event driven code, and must use logic code only:

Webservice

The Phidget Webservice allows you to remotely control a Phidget over a network.
Before using these webservice drivers, it may help to learn about how the Phidget Webservice works.

Common Problems and Solutions

None yet, yay!

Maybe talk about udev rules?