Microbit basic serial port example

In this example we will create a VB.net program that will read data from the serial port, in this case a Microbit connected to the PC. We will then upload a program to our microbit that sends data via the serial port when a button is pressed.

This is a picture of the app will be creating, as you can see it has a combo box with available comms ports listed, connect and disconnect buttons and a textbox which will display serial data from the microbit. You can see the app running and the results of some key presses

Microbit Code

This was written in python using the Mu editor

[codesyntax lang=”python”]

from microbit import *

while True:
    if button_a.is_pressed():
        print("Button A was pressed")
        sleep(250)
    elif button_b.is_pressed():
        print("Button B was pressed")
        sleep(250)
    sleep(100)

[/codesyntax]

Application Code

[codesyntax lang=”vbnet”]

Imports System.IO.Ports


Public Class frmMicroBit
    Dim WithEvents serialPort As New SerialPort
    Delegate Sub myMethodDelegate(ByVal 

 As String)

    Dim myDelegate As New myMethodDelegate(AddressOf DisplaySerialText)
    Private Sub GetSerialPortNames()

        For Each sport As String In My.Computer.Ports.SerialPortNames

            cboPorts.Items.Add(sport)

        Next

    End Sub
    Private Sub frmMicroBit_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Try

            GetSerialPortNames()

            cboPorts.SelectedIndex = 0

        Catch

            MsgBox("No ports connected.")

        End Try

    End Sub
    Private Sub btnConnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConnect.Click

        Try

            serialPort.BaudRate = 115200

            serialPort.PortName = cboPorts.SelectedItem.ToString

            serialPort.Parity = Parity.None

            serialPort.DataBits = 8

            serialPort.StopBits = 1

            serialPort.Open()

            If serialPort.IsOpen Then

                btnConnect.Visible = False

                cboPorts.Enabled = False

                btnDisconnect.Visible = True

            End If

        Catch

            serialPort.Close()

        End Try

    End Sub
    Private Sub btnDisconnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisconnect.Click

        Try

            serialPort.Close()

            btnConnect.Visible = True

            btnDisconnect.Visible = False

            cboPorts.Enabled = True

            Exit Sub

        Catch

            MessageBox.Show("Problem closing port")

        End Try

    End Sub
    Sub DisplaySerialText(ByVal myString As String)

        txtSerial.AppendText(myString)

    End Sub
    Private Sub SerialPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles serialPort.DataReceived

        Dim str As String = serialPort.ReadExisting()

        Invoke(myDelegate, str)

    End Sub

End Class

[/codesyntax]
 
Links
I uploaded the example VB.net app to https://drive.google.com/file/d/0B7mkEkhIEzkNMVVMZEZHbW8wUzA/view?usp=sharing

			
            

				            

							                    

						Micro:Bit