Programming Maxi-Bee in Visual Basic

  
 
 

  Although Maxi-Bee comes with it's own software (BeeStep 64) 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.

  
    InitMbee( )      and     SetOutputs (outputs1, outputs2)    
 

    InitMbee() is called somewhere near the start of your program and takes care of all of the USB comms initialisation and prepares the Maxi-Bee for receiving messages.
   SetOutputs(outputs1, outputs2) can then be called at any time during your program to set the output pattern of on's and off's. The parameters Outputs1 and outputs2 are simply 32 bit integer values. In Outputs1 bit0 corresponds to output 1, bit 1 to output2, etc... and in Outputs2 bit0 corresponds to output 33, bit1 to output34 etc...  In each case 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...

  
   

SetOutputs (7, 0)

    
   and the following would turn on outputs 1, 2,  and 34  
   

SetOutputs (3, 2)

    
 

  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 a program excerpt showing how this is done...

  
 

Declare Function InitMbee Lib "mxb.dll" () As Boolean

Declare Function SetOutputs Lib "mxb.dll" (ByVal Outputs1 As Integer, ByVal Outputs2 As Integer) As Boolean

  
 

   The first declaration states that the function InitMbee has no parameters, is found in mxb.dll and returns a boolean value. The second states that SetOutputs has two integer parameters passed by value rather than reference, is found in mxb.dll  and also returns a boolean value. It should be noted that the

 
   

Lib "mxb.dll"

    
 

   lets the program know where to find the mxb.dll file. When written like this it assumes, since there is no path information, that the mxb.dll file can be found in the windows system directory    c:\windows\system32         If you like you can copy the file mxb.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 in the example below...

  
    Declare Function InitMbee Lib "c:\mylibrary\mxb.dll" () As Boolean    
                   
 

   To speed up your development of software for the Maxi-Bee a complete working example is available for download below. It is called VBmaxi and creates a very simple form based program that has individual buttons for various functions such as initialising the Maxi-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 this application.
 
  



   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

        
                   
                   
 

.      .

  
 

© Copyright pc-control.co.uk 2008