B4R Library rESP32Bluetooth - Esp32 Classic Bluetooth

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Erel

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Very simple to use Bluetooth library for ESP32 modules.

Note that you need to have a recent version of ESP32 SDK. If you encounter any error then download the complete SDK: https://github.com/espressif/arduino-esp32 and copy it to ESP32 SDK folder:
C:\Users\<user>\Documents\Arduino\hardware\espressif\esp32

Instructions:
1. Initialize a ESP32Bluetooth object. You pass the name and the StateChanged event sub. It returns True if it was successful.

2. Initialize an AsyncStreams object with bt.Stream. Based on my tests the connection is not 100% stable when you send a lot of data. It is therefore recommended to use non-prefix mode.

3. The StateChanged event will be raised whenever the connection state changes. AStreams_Error will never be raised.

Example of Bluetooth chat with an Android device:



The B4A project is attached.

B4R code:
B4X:
#Region Project Attributes
   #AutoFlushLogs: True
   #CheckArrayBounds: True
   #StackBufferSize: 600
#End Region

Sub Process_Globals
   Public Serial1 As Serial
   Private bt As ESP32Bluetooth
   Private astream As AsyncStreams
End Sub

Private Sub AppStart
   Serial1.Initialize(115200)
   Log("AppStart")
   If bt.Initialize("Test1", "bt_StateChanged") = False Then
       Log("Failed to start Bluetooth")
       Return
   End If
   astream.Initialize(bt.Stream, "astream_NewData", "astream_Error")
End Sub

Sub bt_StateChanged (Connected As Boolean)
   Log("connected: ", Connected)
End Sub

Sub AStream_Error
   Log("error")
End Sub

Sub AStream_NewData (Buffer() As Byte)
   Log("NewData: ", Buffer)
   astream.Write("Echo from ESP32: ")
   astream.Write(Buffer)
   bt.Stream.Flush
End Sub
 

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iCAB

Well-Known Member
Licensed User
For those who want to automate the test, this can come in handy

1. In the B4R project, change AStream_NewData as follows

B4X:
Sub AStream_NewData (Buffer() As Byte)
    Log("NewData: ", Buffer)
    astream.Write(Buffer)
    bt.Stream.Flush
End Sub

In the B4A project, you can replace ChatActivity code with the code below.

With this code you will be able to run 2 different tests:
1. Test1,
  • Sends a fixed length message and attaches a count value to it.
  • On receive, the message is validated.
  • The count is outputted to the GUI.
  • If the validation fails, an error is displayed and the send loop is terminated

2. Test2 : To run Test2, type "INC", in the input box before clicking send
  • Test2 increments the length of the message by 1 with every loop until an error is triggered.
I have noticed that Test2 fails when the message length gets to 101



B4X:
#Region Module Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

'Activity module
Sub Process_Globals
    
    Dim blnSendLoopOn As Boolean = False
    Dim iSendCounter As Int
    
        'Don't include a "_" in this message
    Dim BaseMessageToSend As String = "0123456789:0123456789:01234567890:0123456789:0123456789:0123456789:01234567890:0123456789"
    Dim MsgSent As String = ""
    
    Dim pw As PhoneWakeState
    Dim blnCounterMode As Boolean = True
    
End Sub

Sub Globals
    Private txtInput As EditText
    Private txtLog As EditText
    Private btnSend As Button
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("2")
    
    pw.KeepAlive(False)
End Sub

Public Sub NewMessage (Msg As String)
    'LogMessage("You", msg)
    Dim MsgToDisplay As String = ""
    
    If blnSendLoopOn = True Then
        If blnCounterMode = True Then
            Dim Components() As String = Regex.Split("_", Msg )
            If Components.Length = 2 Then
                If Components(1) = iSendCounter And Components(0) = BaseMessageToSend Then
                    iSendCounter = iSendCounter + 1
                    SendLoop
                    
                    If (iSendCounter Mod 50) = 0 Then
                        MsgToDisplay  = "The time is: " & DateTime.Time( DateTime.Now ) &  ", Messages Sent: " & iSendCounter
                        Log(MsgToDisplay)
                        LogMessage("",MsgToDisplay)
                    End If
                Else
                    blnSendLoopOn = False
                    MsgToDisplay = "Error at:" & iSendCounter
                    LogMessage("", MsgToDisplay)
                    Log(MsgToDisplay)
                    Log("Sent: " & MsgSent )
                    Log("Recv: " & Msg )
                End If
            End If
        Else
            If Msg = MsgSent Then
                MsgToDisplay = "Received Ok: " & Msg.Length & " Chars"
                SendLoop
            Else
                MsgToDisplay = "Failed, Received: " & Msg.Length & "Chars" & " Sent: " & MsgSent.Length & "Chars"
                blnSendLoopOn = False
            End If
            LogMessage("", MsgToDisplay)
            Log(MsgToDisplay)
            
        End If
    End If
    
    If blnSendLoopOn = False Then
        UpdateButtonText
    End If
    
End Sub



Sub Activity_Resume
    UpdateState
End Sub

Public Sub UpdateState
    btnSend.Enabled = Starter.Manager.ConnectionState
End Sub

Sub Activity_Pause (UserClosed As Boolean)
    If UserClosed Then
        Starter.Manager.Disconnect
    End If
End Sub

Sub txtInput_EnterPressed
    If btnSend.Enabled = True Then btnSend_Click
End Sub


Sub btnSend_Click
    
    If txtInput.Text.ToUpperCase = "INC" Then
        blnCounterMode = False
    Else
        blnCounterMode = True
    End If
    
    iSendCounter = 0
    
    If blnSendLoopOn = False Then
        MsgSent = ""
        SendLoop
    End If
    
    blnSendLoopOn = Not(blnSendLoopOn)
    
    UpdateButtonText
    
'    Starter.Manager.SendMessage(txtInput.Text)
'    txtInput.SelectAll
'    txtInput.RequestFocus
'    LogMessage("Me", txtInput.Text)
End Sub

Sub UpdateButtonText()
    If blnSendLoopOn = True Then
        btnSend.Text = "Stop"
    Else
        btnSend.Text = "Send"
    End If
End Sub


Sub SendLoop()
    If blnCounterMode = True Then
        MsgSent = BaseMessageToSend & "_" & iSendCounter
    Else
        MsgSent = MsgSent & "A"
    End If       
    Starter.Manager.SendMessage( MsgSent )
End Sub





Sub LogMessage(From As String, Msg As String)
    txtLog.Text = txtLog.Text & From & ": " & Msg & CRLF
    txtLog.SelectionStart = txtLog.Text.Length
End Sub
 

viriato

Member
Licensed User
Hello
I am trying the example and i got the following error ..it looks like the mbed.h library is missing

"C:\Users\fvict\DOCUME~1\B4R\NOUVEA~1\Objects\bin\preproc\ctags_target_for_gcc_minus_e.cpp"
In file included from C:\Users\fvict\DOCUME~1\B4R\NOUVEA~1\Objects\bin\sketch\B4RDefines.h:22:0,
from C:\Users\fvict\DOCUME~1\B4R\NOUVEA~1\Objects\src\src.ino:1:
C:\Users\fvict\Documents\Arduino\hardware\espressif\esp32\libraries\BluetoothSerial/BluetoothSerial.h:8:18: fatal error: mbed.h: No such file or directory
compilation terminated.
Using library BluetoothSerial in folder: C:\Users\fvict\Documents\Arduino\hardware\espressif\esp32\libraries\BluetoothSerial (legacy)
exit status 1
--------------------------------------------
Any suggestion will be welcome
Thanks
 

viriato

Member
Licensed User
Hi
I made the re-install again and I am able to compile now..

Thank you for the prompt feedback
 
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