Programming PC-Bee in Visual Basic

  
 
 

  Although PC-Bee comes with it's own software (BeeStep) to allow the beginner to start using it in home automation projects very quickly, it also comes with a DLL interface to allow the intermediate and advanced user to write their own programs for it. The DLL provides a general purpose interface that greatly simplifies the task of writing programs for a USB device.  It can be tricky manipulating the USB comms into sending and receiving messages to and from a device which can easily be plugged and unplugged at any time.  The DLL eliminates all of these headaches by simplifying the task into two library functions.

  
    BeeInit()      and     BeeOut(outputs)    
 

    BeeInit() is called somewhere near the start of your program and takes care of all of the USB comms initialisation and prepares the PC-Bee for receiving messages.
   BeeOut(outputs) can then be called at any time during your program to set the output pattern of on's and off's. The parameter Outputs is simply a 32 bit integer value where bit0 corresponds to output 1, bit 1 to output2, etc... Where a logic value of 1 turns the output on and a value of 0 turns it off. For example the statement below would turn on the first three outputs...

  
   

BeeOut(7)

    
 

  The only other thing that a VB program must do is to declare the functions that it is going to use within the DLL and the name of the DLL itself. This must be done at the start of your program or at least before any references to the two functions are made. The following is an program excerpt showing how this is done...

  
   
Declare Function BeeInit Lib "bee.dll" () As Boolean
Declare Function BeeOut Lib "bee.dll" (ByVal Outputs As Integer) As Boolean
 		    
 

   The first declaration states that the function BeeInit has no parameters, is found in bee.dll and returns a boolean value. The second states that BeeOut has one integer parameter passed by value rather than reference, is found in bee.dll  and also returns a boolean value. It should be noted that the

 
   

Lib "bee.dll"

    
 

   lets the program know where to find the bee.dll file. When written like this it assumes that since there is no path information that the bee.dll file can be found in the windows system directory    c:\windows\system32         If you like you can copy the file bee.dll on the installation disk to the system32 directory and the above statement will work perfectly. Alternatively you can copy the file to some other location and give that location in the declaration as below...

  
    Declare Function BeeInit Lib "c:\library\bee.dll" () As Boolean    
                   
 

   To speed up your development of software for the PC-Bee a complete working example is available for download below. It is called VBbee and creates a very simple form based program that has individual buttons for various functions such as initialising the PC-Bee and setting various patterns on the outputs. The main (and only) screen is shown on the right.  This has been written using Microsoft Visual Studio .net and the download files contain the full workspace (solution) details  to allow you to immediately open and start editing or running.
 
  



   Even if you don't have Visual Studio, the source code is virtually self explanatory with the most relevant sections being in "Form1.vb" which can even be opened in a simple text editor such as notepad. The files are zipped for convenience and may be downloaded by right clicking on the link below and choosing "save target as" to begin the download.

 
                   
     

Download Files

        
                   
                 
 

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