Arduino and Visual Basic Part 3: Controlling an Arduino

I am still very new to Visual Basic and I have been surprised at how quickly you can develop working apps. My first attempt resulted in a very basic app to receive data from the Arduino which taught me the basics of serial communication in VB. The next step is two way communication and controlling the Arduino from the VB program. I already have a similar project arduinoBTcontrol, where the Arduino is controlled from an Android app over Bluetooth. So all I need do is tweek the Arduino sketch and recreate the Android app in VB.

Here is the app screen.Visually it is nothing special and all controls are straight out of VB but is it working well.
ArduinoVBserial

Here is the circuit. Basically the same circuit as used in the Bluetooth project minus the Bluetooth module.
ArduinoVBserial
arduinoBTcontrol - LED diagram

Serial Communication

The communication between the Arduino and Visual Basic is done using ascii over serial/usb. The data sent to the Ardiono is formatted in to commands which are enclosed in start and end markers; "<" and ">".

In this example there is very little data sent from the Arduino to the host computer and so I have not used start and end markers for the data send from the Arduino. For a more complex project I would enclose all data in markers as an easy way to ensure I receive a complete command.

 

The Commands

Depending on the button / slider used, the VB program sends different commands to the Arduino. I have tried to make the commands easy to read and this makes them longer than they need to be. For example, to turn on the LED connected to pin 4 the command is “<P004ON>”, this can be shortened to “<P41>” by using 1 to mean HIGH and 0 to mean LOW.

 
arduinoVBserial_PINS
P – Pin HIGH/LOW.
– <P001ON>, Pin 001 on or Pin 1 HIGH
– <P001OF>, Pin 001 off or Pin1 1 LOW
The button toggles between ON and OFF. First click turns the LED on, the second click turns the LED off
The Arduino Sketch recognises Pin 4,5,6,7,8,9, and 12

 
arduiniVBserial_Navigation_01
N – Navigation
– <NUON>, U for UP. ON for HIGH
– <NUOF>, U for UP. OF for LOW
The navigation buttons work on button down and button up. When the button is clicked and the button becomes pressed the ON signal is sent. When the button is released the button returns to the up position the OF signal is sent.

There are 4 directions (up, down, left and right) and a OK/Select button
The OK button works with regular mouse clicks.

 
arduinoVBserial_CommandButtons_03
Command buttons.
There are 3 command buttons, these send the following commands
– <CMD01> – red / green flash
– <CMD02> – LED chaser
– <CMD03> – RGB LED cycle colours

The command buttons work in a different way to the other buttons. After a command is sent, the VB program waits for a completed signal from the Arduino. The clicked button becomes inactive until the completed signal is received.

 
arduinoVBserial_RGB_sliders_01
T – RGB slider
<Trrrgggbbb>
– rrr is the decimal value 0-255 for the red LED
– ggg is the decimal value 0-255 for the green LED
– bbb is the decimal value 0-255 for the blue LED
<T000000000> is fully off and <T255255255> is fully on

As soon as one of the RGB sliders is moved the new position is sent to the Arduino.

 
arduinoVBserial_userCommands_01
At the bottom of the window is a text box where any command can be entered by the user. The data entered is enclosed in the start and end markers before being sent to the Arduino.
The commands accepted are FON, FOF, DON, and DOF
– FON / FOF, acknowledgement on/of. If you turn this off the commands buttons never reset.
– DON / DOF, debug on/of. With debug on, the Arduino mirrors the data it receives back to the VB program. The commands are then displayed in the Received Data text box.
arduinoVBserial_ReceivedData_01

The Arduino Sketch

The Arduino sketch waits around for serial data and then depending on the data received does something. Basically turn an LED on or turn one off. Of course once you have the LEDs working you can change the sketch to do what ever you like.

The Arduino expects the data to be enclosed in start and end markers and anything received not contained in the markers is ignored.

Most of the work is done in the parseData() routine. This looks at the data received and reacts accordingly.

/* ****************************************************
Sketch Arduino and Visual Basic Part 3 - Controlling an Arduino
arduinoVBserialcontrol
Arduino controlled by VisualBasic
www.martyncurrey.com
 
Some of the below code is not very elegant but it should be easy to see what is happening.
 
 Pins
 2 
 3 
 4 LED
 5 LED
 6 LED
 7 LED
 8 LED
 9 RGB LED RED PIN
 10 RGB LED GREEN PIN
 11 RGB LED BLUE PIN
 12 LED
 14 LED - LEFT
 15 LED - DOWN
 16 LED - UP
 17 LED - RIGHT
 18 LED - OK
 
Commands
The expected commands are
 
Pin HIGH / LOW
<P001ON> - P001 = Pin 1. ON = HIGH
<P001OF> - P001 = Pin 1. OF = LOW
 
RGB LED / Slider
<Trrrgggbbb> - T is the slider command. rrr is the decimal value 0-255 for the red LED
                                        ggg is the decimal value 0-255 for the green LED
                                        bbb is the decimal value 0-255 for the blue LED
 
Navigation
<NUON> - N = navigation. U for UP. ON for HIGH
<NUOF> - N = navigation. U for UP. OF for LOW
U = up. D = down. L = left. R = right. K = OK/select
 
 
Commands
<CMD01> - red / green flash
<CMD02> - LED chaser
<CMD03> - RGB LED cycle colours
 
Other.
<HELLO>
<FON>
<FOF>
<DON>
<DOF>
 
*/ ///////////////////////////////////////////////////////
 
 
boolean debug = true;
 
// length of command is 20 chrs
// if you need longer commands then increase the size of numChars
const byte numChars = 20;
char receivedChars[numChars];
 
boolean newData = false;
 
unsigned int red = 255;
unsigned int green = 255;
unsigned int blue = 255;
 
byte UPpin = 16;
byte DOWNpin = 15;
byte LEFTpin = 14;
byte RIGHTpin = 17;
byte OKpin = 18;
 
boolean feedback = true;
 
 
void setup() 
{
     pinMode(12, OUTPUT); 
     pinMode(8, OUTPUT); 
     pinMode(7, OUTPUT); 
     pinMode(6, OUTPUT); 
     pinMode(5, OUTPUT); 
     pinMode(4, OUTPUT); 
 
     pinMode(11, OUTPUT);
     pinMode(10, OUTPUT);
     pinMode(9, OUTPUT);
 
     // Common anode RGB lED, 255 is off.
     // If using a common cathod RGB lED then remove the next 3 lines.
     analogWrite(9, red);
     analogWrite(10, green);
     analogWrite(11, blue);  
 
     pinMode(14, OUTPUT); 
     pinMode(15, OUTPUT);      
     pinMode(16, OUTPUT);      
     pinMode(17, OUTPUT); 
     pinMode(18, OUTPUT);   
 
     Serial.begin(9600);
     sendStartMessage();
}
 
void loop() 
{
     if (Serial.available() > 0)     {  recvWithStartEndMarkers(); }
     if (newData) { parseData(); }
}     
 
 
 
/*********************
* sends a start up message over serial.
* Assumes serial is connected
* 
* Global:
*       debug
* Local:
* 
*/   
void sendStartMessage()
{
     Serial.println(" "); 
     Serial.println("arduinoVBserialControl Ver 1.0"); 
     Serial.println(" "); 
     Serial.println("DON = debug on"); 
     Serial.println("DOF = debug off"); 
     Serial.println("START to reset"); 
     Serial.println(" "); 
 
     if (debug) { Serial.println("Debug is on"); }
           else { Serial.println("Debug is off"); }
    Serial.println(" "); 
}
 
 
 
 
/*********************
* Checks receivedChars[] for commands
* 
* Global:
*  receivedChars[]
*  newData;
* 
* Local:
* 
*/      
void parseData()
{  
        newData = false;    
        if (debug) { Serial.println( receivedChars ); }    
 
        // HELLO
        // If the Arduino receives "HELLO" it sends "HELLO" back
        // This is used by the VB program to show it is connected
        if (strcmp(receivedChars, "HELLO")  == 0)
        {
            Serial.println("HELLO");
 
            //Blink the LED on pin 13 to show "HELLO" was received
            digitalWrite(13,HIGH); 
            delay(100);
            digitalWrite(13,LOW); 
        }
 
        if (strcmp(receivedChars, "START")  == 0)
        {
            sendStartMessage();
        }
 
 
        // PIN
        // P001ON - P for pin. 001 is the button number. ON = on
        // P001OF - P for pin. 001 is the button number. OF = off
        if (receivedChars[0] == 'P'  )  
        {
             int tmp = convertToNumber( 1 ); 
             if ( receivedChars[4] == 'O' && receivedChars[5] == 'N' ) { digitalWrite(tmp,HIGH); }
             if ( receivedChars[4] == 'O' && receivedChars[5] == 'F' ) { digitalWrite(tmp,LOW);  }
        } // PIN
 
 
 
        // RGB SLIDER
        // Trrrgggbbb
        if  ( receivedChars[0] == 'T' )
        {  
            // For a common anode RGB LED take the value away from 255.
            // If using a common cathod RGB led then use:
            // red = convertToNumber( 1 );  
            // green  = convertToNumber( 4 );
            // blue = convertToNumber( 7 );  
 
            red = 255 - convertToNumber( 1 );  
            green  = 255 - convertToNumber( 4 );
            blue = 255 - convertToNumber( 7 );  
            analogWrite(9, red);
            analogWrite(10, green);
            analogWrite(11, blue);            
        }  // RGB SLIDER       
 
 
 
        // NAVIGATION
        // NUON - N = navigation. U for UP. ON for on
        // NUOF - N = navigation. U for UP. OF for off
        if ( receivedChars[0] == 'N' )  
        {
              if ( receivedChars[1] == 'U' )   // UP
              { 
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'N'  ) { digitalWrite(UPpin,HIGH); }
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'F'  ) { digitalWrite(UPpin,LOW); }
              }
 
              if ( receivedChars[1] == 'D' )   // UP
              {
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'N'  ) { digitalWrite(DOWNpin,HIGH); }
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'F'  ) { digitalWrite(DOWNpin,LOW); }
              }
 
              if ( receivedChars[1] == 'L' )   // UP
              {
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'N'  ) { digitalWrite(LEFTpin,HIGH); }
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'F'  ) { digitalWrite(LEFTpin,LOW); }              
 
              }
 
              if ( receivedChars[1] == 'R' )   // UP
              {
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'N'  ) { digitalWrite(RIGHTpin,HIGH); }
                  if ( receivedChars[2] == 'O'  && receivedChars[3] == 'F'  ) { digitalWrite(RIGHTpin,LOW); }              
              }
 
              if ( receivedChars[1] == 'K' )   // UP
              {
                   if ( receivedChars[2] == 'O'  && receivedChars[3] == 'K'  ) 
                   {   digitalWrite(OKpin,HIGH); 
                       delay(75);
                       digitalWrite(OKpin,LOW);
                   }              
              }
 
        } // NAVIGATION
 
 
 
        //COMMAND
        //CMD01
        //CMD02
        //CMD03
        // do not really need 3 characters. A single "C" would do.
        if ( receivedChars[0] == 'C'  && receivedChars[1] == 'M'  && receivedChars[2] == 'D' )  
        {        
 
              if ( receivedChars[4] == '1')
              {           
                    for ( byte Count = 1; Count <= 15; Count++) 
                    {
                        digitalWrite(4,HIGH); delay(100); digitalWrite(4,LOW); 
                        digitalWrite(12,HIGH); delay(100); digitalWrite(12,LOW); 
                    }
                    if (feedback) { sendOK(1); }
             }     
 
 
              if ( receivedChars[4] == '2')
              { 
                    for ( byte Count = 1; Count <= 5; Count++) 
                    {
                        digitalWrite(4,HIGH);  delay(100); digitalWrite(4,LOW); 
                        digitalWrite(5,HIGH);  delay(100); digitalWrite(5,LOW); 
                        digitalWrite(6,HIGH);  delay(100); digitalWrite(6,LOW); 
                        digitalWrite(7,HIGH);  delay(100); digitalWrite(7,LOW); 
                        digitalWrite(8,HIGH);  delay(100); digitalWrite(8,LOW); 
                        digitalWrite(12,HIGH); delay(100); digitalWrite(12,LOW); 
                    }
                    if (feedback) { sendOK(2); }
              }
 
 
              if ( receivedChars[4] == '3')
              {   
 
                  red = 255; green = 255; blue = 255;
                  for(int red = 255; red >0;    red--)        {  analogWrite(9, red);     delay (5);   } 
                  for(int red = 0;   red < 256; red++)        {  analogWrite(9, red);     delay (5);   } 
                  for(int green = 255; green >0;    green--)  {  analogWrite(10, green);  delay (5);   } 
                  for(int green = 0;   green < 256; green++)  {  analogWrite(10, green);  delay (5);   } 
                  for(int blue = 255; blue >0;    blue--)     {  analogWrite(11, blue);   delay (5);   } 
                  for(int blue = 0;   blue < 256; blue++)     {  analogWrite(11, blue);   delay (5);   } 
                  if (feedback) { sendOK(3); }
              }        
 
        }  // COMMAND
 
 
        // Typed commands -------------------------------------------------------
 
        if (strcmp(receivedChars, "DON")  == 0)  
        {
              if ( receivedChars[1] =='O'  && receivedChars[2] =='F' )  {  debug = false;  Serial.println("Debug is off"); }
        }
        if (strcmp(receivedChars, "DOF")  == 0)  
        {
              if ( receivedChars[1] =='O'  && receivedChars[2] =='F' )  {  debug = false;  Serial.println("Debug is off"); }
        }
 
 
        // ACKNOWLEDGMENT
        // FON
        // FOF
        if  ( receivedChars[0] == 'F' )
        {
           if ( receivedChars[1] =='O'  && receivedChars[2] =='N' )  {  feedback = true;    }
           if ( receivedChars[1] =='O'  && receivedChars[2] =='F' )  {  feedback = false;    }
 
           if (feedback) { Serial.println("acknowledgment is on");  } 
           else          { Serial.println("acknowledgment is off"); } 
        }  // FEEDBACK  
 
 
 
        if  ( receivedChars[0] == 'D' )
        {
              if ( receivedChars[1] =='O'  && receivedChars[2] =='N' )  {  debug = true;   Serial.println("Debug is on"); }
              if ( receivedChars[1] =='O'  && receivedChars[2] =='F' )  {  debug = false;  Serial.println("Debug is off"); }
        }
 
}
 
 
/*********************
* Takes seial input and looks for data between a start and end marker.
* 
* Global:
*  Updates receivedChars[] with the received data
* 
* Local:
* 
*/ 
void recvWithStartEndMarkers() 
{
 
// function recvWithStartEndMarkers by Robin2 of the Arduino forums
// See  http://forum.arduino.cc/index.php?topic=288234.0
 
     static boolean recvInProgress = false;
     static byte ndx = 0;
     char startMarker = '<';
     char endMarker = '>';
 
     char rc;
 
     if (Serial.available() > 0) 
     {
          rc = Serial.read();
 
          if (recvInProgress == true) 
          {
               if (rc != endMarker) 
               {
                    receivedChars[ndx] = rc;
                    ndx++;
                    if (ndx >= numChars) { ndx = numChars - 1; }
               }
               else 
               {
                     receivedChars[ndx] = '\0'; // terminate the string
                     recvInProgress = false;
                     ndx = 0;
                     newData = true;
               }
          }
 
          else if (rc == startMarker) { recvInProgress = true; }
     }
 
}
 
 
 
/*********************
* converts 3 ascii characters to a numeric value
* 
* Global:
*  Expects receivedChars[] to contain the ascii characters
* 
* Local:
*  startPos is the position of the first character
* 
* 
*/
 
int convertToNumber( byte startPos)
{
  unsigned int tmp = 0;
  tmp = (receivedChars[startPos]-48) * 100;
  tmp = tmp + (receivedChars[startPos+1]-48) * 10;
  tmp = tmp + receivedChars[startPos+2]-48;  
  return tmp;
}
 
 
 
void sendOK(int val)
{
  // The 3 command buttons wait for the OK signal
  Serial.print("OK");Serial.println(val);
}

The Visual Basic Program

The program is written in VB2013 which is part of the Visual Studio package. I am using Visual Studio 2013 Community which is a full development package and available for free for hobbyists, students and freelance developers. Visual Studio 2013 Community is available for download at https://www.visualstudio.com/en-us/products/visual-studio-community-vs.aspx.

The VB program waits for the user to press a button or move a slider and then sends the appropriate command to the Arduino

ArduinoVBserial_004

' arduinoVBserial
' Arduino and Visual Basic: Receiving Data From the Arduino
' A simple example of sending and receiving data to and from an Arduino
'
 
Imports System
Imports System.IO.Ports
 
 
 
Public Class Form1
    ' Global variables
    Dim comPORT As String
    Dim receivedData As String = ""
    Dim connected As Boolean = False
    Dim count = 0
 
    ' When the program starts; make sure the timer is off (not really needed) and add the available COM ports to the COMport drop down list
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Timer1.Enabled = False
        populateCOMport()
    End Sub
 
    'The refresh button updates the COMport list
    Private Sub refreshCOM_BTN_Click(sender As Object, e As EventArgs) Handles refreshCOM_CB_BTN.Click
        SerialPort1.Close()
        populateCOMport()
    End Sub
 
    Private Sub populateCOMport()
        comPORT = ""
        comPort_ComboBox.Items.Clear()
        For Each sp As String In My.Computer.Ports.SerialPortNames
            comPort_ComboBox.Items.Add(sp)
        Next
    End Sub
 
    Private Sub comPort_ComboBox_SelectedIndexChanged(sender As Object, e As EventArgs) Handles comPort_ComboBox.SelectedIndexChanged
        If (comPort_ComboBox.SelectedItem <> "") Then
            comPORT = comPort_ComboBox.SelectedItem
        End If
    End Sub
 
    ' When the Connect button is clicked; if a COM port has been selected, connect and send out a HELLO message.
    ' Then wait for the Arduino to respond with its own HELLO.
    ' When the HELLO is received we are connected; change the button text to Dis-connect.
    Private Sub connect_BTN_Click(sender As Object, e As EventArgs) Handles connect_BTN.Click
        comPORT = comPort_ComboBox.SelectedItem
        If (connect_BTN.Text = "Connect") Then
            If (comPORT <> "") Then
                SerialPort1.Close()
                SerialPort1.PortName = comPORT
                SerialPort1.BaudRate = 9600
                SerialPort1.DataBits = 8
                SerialPort1.Parity = Parity.None
                SerialPort1.StopBits = StopBits.One
                SerialPort1.Handshake = Handshake.None
                SerialPort1.Encoding = System.Text.Encoding.Default
                SerialPort1.ReadTimeout = 10000
 
                SerialPort1.Open()
 
                'See if the Arduino is there
                count = 0
                SerialPort1.WriteLine("<HELLO>")
                connect_BTN.Text = "Connecting..."
                connecting_Timer.Enabled = True
            Else
                MsgBox("Select a COM port first")
            End If
        Else
            'connect_BTN.Text = "Dis-connect"
            'close the connection a reset the button and timer label
            Timer1.Enabled = False
            Timer_LBL.Text = "Timer: OFF"
            SerialPort1.Close()
            connected = False
            connect_BTN.Text = "Connect"
            populateCOMport()
        End If
 
 
    End Sub
 
    'The connecting_Timer waits for the Arduino to say HELLO.
    ' If HELLO is not received in 2 seconds display an error message.
    ' The connecting_Timer is only used for connecting
    Private Sub connecting_Timer_Tick(sender As Object, e As EventArgs) Handles connecting_Timer.Tick
        connecting_Timer.Enabled = False
        count = count + 1
 
        If (count <= 8) Then
            receivedData = receivedData & ReceiveSerialData()
 
            If (Microsoft.VisualBasic.Left(receivedData, 5) = "HELLO") Then
                'if we get an HELLO from the Arduino then we are connected
                connected = True
                connect_BTN.Text = "Dis-connect"
                Timer1.Enabled = True
                Timer_LBL.Text = "Timer: ON"
                receivedData = ReceiveSerialData()
                receivedData = ""
                SerialPort1.WriteLine("<START>")
 
            Else
                'start the timer again and keep waiting for a signal from the Arduino
                connecting_Timer.Enabled = True
            End If
 
 
        Else
            'time out (8 * 250 = 2 seconds)
            RichTextBox1.Text &= vbCrLf & "ERROR" & vbCrLf & "Can not connect" & vbCrLf
            connect_BTN.Text = "Connect"
            populateCOMport()
        End If
 
 
 
    End Sub
 
 
 
 
 
    'After a connection is made the main timer waits for data from the Arduino
    'Only OK1, OK2 or OK3 is available.
    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        receivedData = ReceiveSerialData()
        RichTextBox1.Text &= receivedData
 
        Dim tmp As String
        tmp = Microsoft.VisualBasic.Left(receivedData, 3)
 
        If (tmp = "OK1") Then
            cmd1_BTN.Enabled = True
        End If
 
        If (tmp = "OK2") Then
            cmd2_BTN.Enabled = True
        End If
 
        If (tmp = "OK3") Then
            cmd3_BTN.Enabled = True
        End If
 
    End Sub
 
    Function ReceiveSerialData() As String
        Dim Incoming As String
        Try
            Incoming = SerialPort1.ReadExisting()
            If Incoming Is Nothing Then
                Return "nothing" & vbCrLf
            Else
                Return Incoming
            End If
        Catch ex As TimeoutException
            Return "Error: Serial Port read timed out."
        End Try
 
    End Function
 
 
    'Clear the RecievedData text box
    Private Sub clear_BTN_Click(sender As Object, e As EventArgs) Handles clear_BTN.Click
        RichTextBox1.Text = ""
    End Sub
 
 
 
 
    'LED buttons
    ' This is a basic example and to keep the code simple each button has a separate function. The code could be reduced by using the sender object 
    'If the Arduino is not connected a nessage box display an error message
    Private Sub Pin4_BTN_Click(sender As Object, e As EventArgs) Handles Pin4_BTN.Click
        If (connected) Then
            If (Pin4_BTN.Text = "4 OFF") Then
                SerialPort1.WriteLine("<P004ON>")
                Pin4_BTN.Text = "4 ON"
            Else
                SerialPort1.WriteLine("<P004OF>")
                Pin4_BTN.Text = "4 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
    Private Sub Pin5_BTN_Click(sender As Object, e As EventArgs) Handles Pin5_BTN.Click
        If (connected) Then
            If (Pin5_BTN.Text = "5 OFF") Then
                SerialPort1.WriteLine("<P005ON>")
                Pin5_BTN.Text = "5 ON"
            Else
                SerialPort1.WriteLine("<P005OF>")
                Pin5_BTN.Text = "5 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
    Private Sub Pin6_BTN_Click(sender As Object, e As EventArgs) Handles Pin6_BTN.Click
        If (connected) Then
            If (Pin6_BTN.Text = "6 OFF") Then
                SerialPort1.WriteLine("<P006ON>")
                Pin6_BTN.Text = "6 ON"
            Else
                SerialPort1.WriteLine("<P006OF>")
                Pin6_BTN.Text = "6 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
    Private Sub Pin7_BTN_Click(sender As Object, e As EventArgs) Handles Pin7_BTN.Click
        If (connected) Then
            If (Pin7_BTN.Text = "7 OFF") Then
                SerialPort1.WriteLine("<P007ON>")
                Pin7_BTN.Text = "7 ON"
            Else
                SerialPort1.WriteLine("<P007OF>")
                Pin7_BTN.Text = "7 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
    Private Sub Pin8_BTN_Click(sender As Object, e As EventArgs) Handles Pin8_BTN.Click
        If (connected) Then
            If (Pin8_BTN.Text = "8 OFF") Then
                SerialPort1.WriteLine("<P008ON>")
                Pin8_BTN.Text = "8 ON"
            Else
                SerialPort1.WriteLine("<P008OF>")
                Pin8_BTN.Text = "8 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
    Private Sub Pin12_BTN_Click(sender As Object, e As EventArgs) Handles Pin12_BTN.Click
        If (connected) Then
            If (Pin12_BTN.Text = "12 OFF") Then
                SerialPort1.WriteLine("<P012ON>")
                Pin12_BTN.Text = "12 ON"
            Else
                SerialPort1.WriteLine("<P012OF>")
                Pin12_BTN.Text = "12 OFF"
            End If
        Else
            MsgBox("Not connected")
        End If
    End Sub
 
 
 
 
    'Command buttons
    Private Sub cmd1_BTN_Click(sender As Object, e As EventArgs) Handles cmd1_BTN.Click
        If (connected) Then
            SerialPort1.WriteLine("<CMD01>")
            cmd1_BTN.Enabled = False
        End If
    End Sub
 
    Private Sub cmd2_BTN_Click(sender As Object, e As EventArgs) Handles cmd2_BTN.Click
        If (connected) Then
            SerialPort1.WriteLine("<CMD02>")
            cmd2_BTN.Enabled = False
        End If
    End Sub
 
    Private Sub cmd3_BTN_Click(sender As Object, e As EventArgs) Handles cmd3_BTN.Click
        If (connected) Then
            SerialPort1.WriteLine("<CMD03>")
            cmd3_BTN.Enabled = False
        End If
    End Sub
 
 
 
 
    'RGB sliders
    Private Sub red_TrackBar_Scroll(sender As Object, e As EventArgs) Handles red_TrackBar.Scroll
        updateRGBlbl()
    End Sub
 
    Private Sub green_TrackBar_Scroll(sender As Object, e As EventArgs) Handles green_TrackBar.Scroll
        updateRGBlbl()
    End Sub
 
    Private Sub blue_TrackBar_Scroll(sender As Object, e As EventArgs) Handles blue_TrackBar.Scroll
        updateRGBlbl()
    End Sub
 
    Private Sub updateRGBlbl()
        slider_LBL.Text = "R:" & Format(red_TrackBar.Value, "000") & "  G:" & Format(green_TrackBar.Value, "000") & "  B:" & Format(blue_TrackBar.Value, "000")
        If (connected) Then
            Dim data As String
            data = "<T" & Format(red_TrackBar.Value, "000") & Format(green_TrackBar.Value, "000") & Format(blue_TrackBar.Value, "000") & ">"
            SerialPort1.WriteLine(data)
        End If
 
    End Sub
 
 
 
 
 
 
    'Navigation buttons
    Private Sub up_BTN_MouseDown(sender As Object, e As MouseEventArgs) Handles up_BTN.MouseDown
        If (connected) Then
            SerialPort1.WriteLine("<NUON>")
        End If
    End Sub
 
    Private Sub up_BTN_MouseUp(sender As Object, e As MouseEventArgs) Handles up_BTN.MouseUp
        If (connected) Then
            SerialPort1.WriteLine("<NUOF>")
        End If
    End Sub
 
    Private Sub down_BTN_MouseDown(sender As Object, e As MouseEventArgs) Handles down_BTN.MouseDown
        If (connected) Then
            SerialPort1.WriteLine("<NDON>")
        End If
    End Sub
 
    Private Sub down_BTN_MouseUp(sender As Object, e As MouseEventArgs) Handles down_BTN.MouseUp
        If (connected) Then
            SerialPort1.WriteLine("<NDOF>")
        End If
    End Sub
 
    Private Sub left_BTN_MouseDown(sender As Object, e As MouseEventArgs) Handles left_BTN.MouseDown
        If (connected) Then
            SerialPort1.WriteLine("<NLON>")
        End If
    End Sub
 
    Private Sub left_BTN_MouseUp(sender As Object, e As MouseEventArgs) Handles left_BTN.MouseUp
        If (connected) Then
            SerialPort1.WriteLine("<NLOF>")
        End If
    End Sub
 
    Private Sub right_BTN_MouseDown(sender As Object, e As MouseEventArgs) Handles right_BTN.MouseDown
        If (connected) Then
            SerialPort1.WriteLine("<NRON>")
        End If
    End Sub
 
    Private Sub right_BTN_MouseUp(sender As Object, e As MouseEventArgs) Handles right_BTN.MouseUp
        If (connected) Then
            SerialPort1.WriteLine("<NROF>")
        End If
    End Sub
 
 
    'The OK button acts as soon as the button is clicked. It does not wait for the user to release the button
    'There is no of for the OK button
    Private Sub ok_BTN_MouseDown(sender As Object, e As MouseEventArgs) Handles ok_BTN.MouseDown
        If (connected) Then
            SerialPort1.WriteLine("<NKOK>")
        End If
 
    End Sub
 
 
 
    'Add the start and end markers to the contents of the text box and then send to the Arduino.
    'Does not clear the contents
    Private Sub send_BTN_Click(sender As Object, e As EventArgs) Handles send_BTN.Click
        If (connected) Then
            Dim tmp As String
            tmp = "<" & send_TB.Text & ">"
            SerialPort1.WriteLine(tmp)
        End If
    End Sub
 
 
End Class

Connecting

To connect to the Arduino selected the appropriate COM port and click the connect button. The VB program will make a connection and send a HELLO message to the Arduino. If the Arduino replies then we are connected and the button text changes. If no reply is received then an error message is displayed.

 

Next steps

– add different functions such as motor control or send sensor data from teh Arduino to the VB program,
– add regular checks to see if the Arduino is connected
– reset the command buttons when acknowledgement is turned off
– reset the Arduino when disconnected

 

Download

Download the Arduino Sketch, the VB program(exe file) and the VB2013 project files


 
 

21 thoughts on “Arduino and Visual Basic Part 3: Controlling an Arduino

  1. Pingback: Quick Links | Martyn Currey

  2. I was wondering how you might implement different functions with the command buttons, for instance if I have a function that flashes 2 different pins (i’d like to loop it until another command is received from interface) how could I go about assigning it to button, but still make the arduino listen for the next command?

  3. Pingback: Arduino and Visual Basic Part 1: Receiving Data From the Arduino | Martyn Currey

  4. Hi, I am new to Arduino. My Grandson is coming to visit in August, I bought a Edge robotic arm, AT Mega, and two Adafruit motor sheilds. I got the Arm operating ok, I am using an HMI I wrote in VB. I am sending individual numbers to the AT to run the routines, But can only use the single digits 0 – 9, if i try to send the number 10 for instance, the Arduino sees it as a 1 and a 0, then runs the routine assoc with 1 and then with 0. Would you know what I’m doing wrong?

  5. Hi Jim,

    Serial data is received one character at a time and you need to store the data somewhere until you have the complete code. This is where the recvWithStartEndMarkers() function comes in. This function copies anything it finds in between the < and > markers to the receivedChars variable.

    It would be worth while reading up on serial communications and a good place to start is http://forum.arduino.cc/index.php?topic=288234.0. The function I use is taken directly from this post.

  6. Hi! Thank you for giving us an idea about our project. But is it possible to replace bluetooth module to rf transceiver module? Does the code works the same?

  7. Thank you for a very useful website
    It really helped me on the way.
    I have copied parts of your code, and found no errors :-)

  8. Hello Martyn,

    Big thank u for this example.

    Question:
    I have add 1 TrackBar and try to control PGA2310 audio volume.
    unfortunately i can’t get this working in your code.

    Can someone help me with this issue.
    Thank u.

    The arduino source is working with Rotary encoder:
    arduino PGA2310.ino code;

    #include

    const int PGA_CS_PIN = 11;
    const int PGA_SCLK_PIN = 13;
    const int PGA_SDI_PIN = 12;

    int state, prevstate, volumeLevel, level = 0;
    int nextEncoderState[4] = { 2, 0, 3, 1 };
    int prevEncoderState[4] = { 1, 3, 0, 2 };

    void setup() {
    pinMode(PGA_CS_PIN, OUTPUT);
    pinMode(PGA_SCLK_PIN, OUTPUT);
    pinMode(PGA_SDI_PIN, OUTPUT);

    digitalWrite(PGA_CS_PIN, HIGH);
    digitalWrite(PGA_SCLK_PIN, HIGH);
    digitalWrite(PGA_SDI_PIN, HIGH);

    pinMode(5, INPUT);
    pinMode(6, OUTPUT);
    pinMode(7, INPUT);

    digitalWrite(5, HIGH);
    digitalWrite(6, LOW);
    digitalWrite(7, HIGH);

    Serial.begin(9600);
    }

    void PGA_set_volume(byte value)
    {
    byte shifted_val = (value << 1);
    digitalWrite(PGA_CS_PIN, LOW); // assert CS
    SPI_write(shifted_val); // right value (0..255)
    SPI_write(shifted_val); // right value (0..255)
    digitalWrite(PGA_CS_PIN, HIGH); // deassert CS
    }

    static inline void SPI_write(byte out_spi_byte)
    {
    byte i;
    // loop thru each of the 8-bits in the byte
    for (i = 0; i < 8; i++)
    {
    // strobe clock
    digitalWrite(PGA_SCLK_PIN, LOW);
    // send the bit (we look at the high order bit and 'print' that to the remtoe device)
    if (0x80 & out_spi_byte) // MSB is set
    digitalWrite(PGA_SDI_PIN, HIGH);
    else
    digitalWrite(PGA_SDI_PIN, LOW);
    // unstrobe the clock
    digitalWrite(PGA_SCLK_PIN, HIGH);
    out_spi_byte <<= 1; // left-shift the byte by 1 bit
    }
    }

    void loop()
    {
    state = (digitalRead(7) << 1) | digitalRead(5);
    if (state != prevstate)
    {
    if (state == nextEncoderState[prevstate])
    {
    if (volumeLevel 0)
    {
    volumeLevel = volumeLevel – 1;
    PGA_set_volume(volumeLevel);
    Serial.println(volumeLevel, DEC);
    }
    }
    prevstate = state;
    }
    }

    • unfortunately I cannot help with the complete code but I would suggest breaking the issue in to small problems.

      I presume you are using a PC as a controller, in which case;
      Get the controller working with the Arduino. Display the results in the serial monitor.
      Get the Arduino to control the PGA2310.
      After you have the separate parts working put them together.

      If you have not already, I would also suggest joinging the Arduino forum (and possible the EEVBlog forum).

      • Thanks for the quick response Martyn.

        maybe u can have a look shortly this pice of code?.

        This part of code i have add in the (your) arduino source:
        1, I select the matrix input port first,
        2, then i give the PGA command

        ******************************

        // Volume control

        if ( receivedChars[3] == ‘1’ && receivedChars[4] == ‘5’ && receivedChars[5] == ‘1’ ) // Volume control 1
        {
        for ( byte Count = 1; Count 127)
        {
        volumeLevel = 1 + convertToNumber( 1 );
        }
        // Set the volume
        PGA_set_volume(volumeLevel);
        // Serial.println(volumeLevel);
        volumeLevel = volumeLevel + 1;
        }
        }
        if (feedback) {

        sendOK(151);
        }
        }

        • // Volume control

          if ( receivedChars[3] == ‘1’ && receivedChars[4] == ‘5’ && receivedChars[5] == ‘1’ ) // Volume control 1
          {
          for ( byte Count = 1; Count 127)
          {
          volumeLevel = 1 + convertToNumber( 1 );
          }
          // Set the volume
          PGA_set_volume(volumeLevel);
          // Serial.println(volumeLevel);
          volumeLevel = volumeLevel + 1;
          }
          }
          if (feedback) {

          sendOK(151);
          }
          }

  9. i dont know, but it seems that the some code dissepear.

    for ( byte Count = 1; Count <= 15; Count++)
    {
    connect (0, 0); // Matrix Input 1

    update ();
    update_required = 0;
    }
    if ( receivedChars[0] == 'V' )
    {

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