INTEGRATED EMBEDDED SYSTEM WITH Vb.Net- Chapter 4

GSM INTERFACE

Visit http://researchdesignlab.com/gsm-sim-900.html to buy this product.

There are many different kinds of applications SMS applications in the market today, and many others are being developed. Applications in which SMS messaging can be utilized are virtually unlimited. Some common examples of these are given below:

• Person-to-person text messaging is the most commonly used SMS application, and it is what the SMS technology was originally designed for.
• Many content providers make use of SMS text messages to send information such as news, weather report, and financial data to their subscribers.
• SMS messages can carry binary data, and so SMS can be used as the transport medium of wireless downloads. Objects such as ringtones, wallpapers, pictures, and operator logos can be encoded in SMS messages.
• SMS is a very suitable technology for delivering alerts and notifications of important events.
• SMS messaging can be used as a marketing tool.

In general, there are two ways to send SMS messages from a computer / PC to a mobile phone:

1. Connect a mobile phone or GSM/GPRS modem to a computer / PC. Then use the computer / PC and AT commands to instruct the mobile phone or GSM/GPRS modem to send SMS messages.
2. Connect the computer / PC to the SMS center (SMSC) or SMS gateway of a wireless carrier or SMS service provider. Then send SMS messages using a protocol / interface supported by the SMSC or SMS gateway

AT Commands

AT commands are instructions used to control a modem. AT is the abbreviation of ATtention. Every command line starts with "AT" or "at". That's why modem commands are called AT commands. There are two types of AT commands:

1.       Basic commands are AT commands that do not start with a "+". For example, D (Dial), A (Answer), H (Hook control), and O (Return to online data state) are the basic commands.

2.       Extended commands are AT commands that start with a "+". All GSM AT commands are extended commands. For example, +CMGS (Send SMS message), +CMGL (List SMS messages), and +CMGR (Read SMS messages) are extended commands.

The FORM DESIGN as show below, Here we using combo box for port selection  and textbox for entering mobile number to send sms,and message field to type message and send button.

The complete code as given below, Here we have to create two class 1)sms ,2)program

The class sms will set all pre-requirements in order to send sms,and port values and program class will load the forms and this will initiate the application.

Imports System.Data.SqlClient

Imports System.Net.Sockets

Imports System.Text

 Public Class Form1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        If SerialPort1.IsOpen Then

            SerialPort1.Close()

        End If

        Try

            With SerialPort1

                .PortName = "COM11"

                .BaudRate = 9600

                .Parity = IO.Ports.Parity.None

                .DataBits = 8

                .StopBits = IO.Ports.StopBits.One

                .Handshake = IO.Ports.Handshake.None

                .NewLine = vbCrLf

                .RtsEnable = True

                .RtsEnable = True

            End With

            SerialPort1.Open()

            SerialPort1.WriteLine("at+cmgf=1" & vbCrLf)

        Catch ex As Exception

            MsgBox(ex.ToString)

        End Try

    End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

Dim Num as Integer

Dim Msg as String

Num=TexBox1.text

Msg=TexBox2.text

Send_sms(Num,Msg)

End Sub

Sub send_sms(ByVal Cont_no As String, ByVal acc_details As String)

        Dim Mobile = Cont_no

        Dim message = acc_details

        SerialPort1.WriteLine("at+cmgd=1" & vbCrLf)

        Sleep(1000)

        Dim a As String

        a = "at+cmgs=""+91" & Mobile & """"

        SerialPort1.WriteLine(a & vbCrLf)

        Sleep(1000)

        SerialPort1.WriteLine(message & Chr(26))

    End Sub

End Class

INTEGRATED EMBEDDED SYSTEM WITH Vb.Net- Chapter 3

FT245 RELAY CONTROLLER

Visit  http://researchdesignlab.com/usb-4-channel-relay-board.htmlto buy 4-channel relay  and visit http://researchdesignlab.com/usb-8-channel-relay-board.htmlto buy 8-channel relay.

A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

Here we are making use of 4 channel relay to controlling it, The following picture show the design part of it, in this we have used one combo box for reading com port and open button to open the selected port, and DATA text box, this is for entering manually which relay should turn on suppose if you enter ‘ff’ it will turn on relay1.

The complete source code for controlling 4/8 channel relay.

Imports System.Data.SqlClient

Imports System.Net.Sockets

Imports System.Text

Public Class Form1

Public Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Label11.Text = "Hi" + " " + Form2.TextBox1.Text + " , " + "Welcome you to PSA"

        user = Form2.TextBox1.Text

        total = 0

        k = 0

        If SerialPort1.IsOpen Then

            SerialPort1.Close()

        End If

        Try

            With SerialPort1

                .PortName = "COM5"

                .BaudRate = 9600

                .Parity = IO.Ports.Parity.None

                .DataBits = 8

                .StopBits = IO.Ports.StopBits.One

                .Handshake = IO.Ports.Handshake.None

            End With

            SerialPort1.Open()

        Catch ex As Exception

            MsgBox(ex.ToString)

        End Try

    End Sub         

       Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

                      If SerialPort1.IsOpen Then

            SerialPort1.Close()

        End If

            SerialPort1.Open()

              Button2.Enabled = true

              Button3.Enabled = true

              Button4.Enabled = true

              Button5.Enabled = true

              Button6.Enabled = true

              Button7.Enabled = true

              Button8.Enabled = true

              Button9.Enabled = true

              Button10.Enabled = true

       End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button1.Click       

         

SerialPort1.WriteLine(TextBox1.Text);

       

End Sub

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button1.Click       

            SerialPort1.WriteLine ("02");

       

End Sub

Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button1.Click       

           SerialPort1.WriteLine ("00");

        End Sub

Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button1.Click 

          SerialPort1.WriteLine ("08");

        End Sub

Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button1.Click       

            SerialPort1.WriteLine ("00");

        End Sub

Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button1.Click       

            SerialPort1.WriteLine ("20");

        End Sub

Private Sub Button9_Click(sender As Object, e As EventArgs) Handles Button1.Click       

        SerialPort1.WriteLine ("00");

        End Sub

Private Sub Button8_Click(sender As Object, e As EventArgs) Handles Button1.Click

       

SerialPort1.WriteLine ("80");

        End Sub

Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button1.Click       

SerialPort1.WriteLine ("00");

        End Sub

    End Class