Is it possible to connect to multiple bluetooth modules ??

[tolisn]

Hi.
I want to startup in home automation using my nexus 7 tablet.
I have 3 bluetooth modules ( bluesmirf from sparkfun) and what to be able to connect to all of them so I can send specific commands from my tablet to each one.
Each module has a specific Mac address and a Spesific name.
Has anyone done this sort of project and how ?
Any ideas:sign0085: ?

 

[Beja]

This is what I have been looking for since long time.. some bullet answers didn't help much.
I hope Erel or another fellow member can come up with an example with a spinner of a number of Mac addresses to chose from then pair and connect to the selected one. I know my Mac addresses so NO Need for the search function at all.
A dream.

 

[Erel]

Is it possible to connect to multiple bluetooth modules ??

Yes. You just need to create a Serial object for each connection (and AsyncStream object).

 

[tolisn]

Any example for this ?

 

[Beja]

If Erel and the B4A team took the hardship and long march to present us with this wonderful tool, then it is only fair that we read the documentaion they generously provided for us.
But it is human nature to start with a walker!! and then 4-wheel bike, and that's why all languages start with a complete, self-contained and ready to compile hello world example. When I end this long trip I will go to the nearest Kinko's, opps FedEx and print out all of docs. for me it is much easier and comfortable to brows hardcopy user guide than reading it online.
But until then I hope Erel considers a little detailed replies..
Examples for Dummies!

 

[Erel]

What you are asking doesn't fit a simple example. It is a complete project.

There is no difference between connecting to one device or multiple devices. Start with connecting to the first device. Then you should create another Serial object and create to the second device.

If you have any specific question then I will be happy to help...

 

[tolisn]

What you are asking doesn't fit a simple example. It is a complete project.

There is no difference between connecting to one device or multiple devices. Start with connecting to the first device. Then you should create another Serial object and create to the second device.

If you have any specific question then I will be happy to help...

So does this mean that you can connect the android device to 2 bluetooth modules at the same time ?

I have seen somewhere in the documentation that the serial object can handle only one connection at a time

 

[Erel]

You need one Serial object and one AsyncStreams object for each connection. Your program can include any number of these objects.

 

[tolisn]

You need one Serial object and one AsyncStreams object for each connection. Your program can include any number of these objects.

I did this in my code

Sub Process_Globals
   Dim AStream As AsyncStreams
        Dim AStream2 As AsyncStreams
End Sub

Sub Activity_Create(FirstTime As Boolean)
Activity.LoadLayout("2")

If AStream.IsInitialized = False Then      
AStream.Initialize(Main.Serial1.InputStream, Main.Serial1.OutputStream, "AStreams") 

AStream2.Initialize(Main.Serial2.InputStream, Main.Serial2.OutputStream, "Astreams2")

End If

End Sub

but the code always pauses in the second AStream2.initialize
What could be the problem?


Of course I have also done this

Sub Process_Globals
   Dim admin As BluetoothAdmin
   Dim serial1 As Serial
   Dim serial2 As Serial
   Dim foundDevices As List
   Type NameAndMac (Name As String, Mac As String)
   Dim connectedDevice As NameAndMac
End Sub

and this

Sub Activity_Create(FirstTime As Boolean)
   If FirstTime Then
      admin.Initialize("admin")
      serial1.Initialize("serial1")
      serial2.Initialize("serial2")
   End If
   Activity.LoadLayout("1")
End Sub

 

[Erel]

You should check the logs and find the error message. I recommend you to initialize asyncstreams right after Serial is connected.

 

[tolisn]

I got the below error message


AStream2.Initialize(Main.Serial2.InputStream, Main.Serial2.OutputStream, "AStreams2")
java.lang.NullPointerException


Sometimes the program runs OK and the connection to the 2 bluetooth modules is made without any errors but most of the time I get the above error message and the program stops.

 

[Erel]

You should post the full error message from the logs and also post your code.

 

[tolisn]

Hi Erel.

Attached are the project files as well as the log.txt file.:sign0085:

 

[Erel]

Note that you should use File - Export as zip when uploading files.

It seems like you start the second activity before both streams were connected. You cannot initialize AsyncStreams before the stream is connected.

I recommend you to initialize AsyncStreams in Serial_Connected event. I also recommend you to move all the communication code to one service. It will be simpler.

 

[tolisn]

Hi.
I'm trying to do what you said but since I'm not a programmer I'm having a very hard time understanding your suggestions.
Is it possible to point me to the correct direction?
Sorry for all the questions but it's been 2 days now that I'm trying this but cannot make it work. I do not know what else to do.

 

[Erel]

I'm afraid that that task of creating multiple Bluetooth connections does require some programming knowledge.

The mistake in your code is that you start the activity before both connections are made.

 

[tolisn]

But I can see the bluetooth modules that they connect. Any why is the error happening not always ?

 

[Erel]

You cannot call AsyncStreams.Initialize before there is a connection. I guess that in some cases both connections are established before the second activity is started. You should change your code to make sure that this is the case.