Douglas H. Williams. PDA Robotics. 2003. 256p

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#undef THIS_FILE

static char BASED_CODE THIS_FILE[] = __FILE__;

#endif

IMPLEMENT_DYNAMIC(CPDASocket, CSocket)

CPDASocket::CPDASocket(PURPOSE_E iPurpose):

CCeSocket(iPurpose)

{

}

void CPDASocket::OnReceive(int nErrorCode)

{

// Call the ReadPDAData() that exists in

// the CPDABotDlg class

((CPDABotDlg *)AfxGetApp())->ReadPDAData();

CSocket::OnReceive(nErrorCode);

}

CPDASocket inherits everything from CceSocket, meaning users call

and access all the public member functions and variables. The virtual

function OnReceive(int nErrorCode) is overridden so that users can

implement their own version, but still use the underlying code and

features. Note that the default socket type is set to data.

CCeSocket::CCeSocket

This constructor creates an instance of a socket object.

CCeSocket ( PURPOSE_E iPurpose = FOR_DATA);

Parameters

iPurpose specifies the enumerated constant that designates whether

the socket is to be a listening socket or a data socket. It is one of the

following values:

• FOR_LISTENING

• FOR_DATA

Remarks

When constructing a CCeSocket object, specify whether it is a listen-

ing socket or a data socket. After construction, call the Create method.

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If you do not specify the purpose of the socket, the constructor con-

structs a data socket by default.

OnWireless: Implementing the CPDASocket Class

The following code is from CPDABotDlg and gets called when the user

clicks the Wireless button. It creates the socket, identifying itself as the

name of the PDA it is running on by calling gethostname() and then

initiates the connection with the command center. If it went well, the

command center will send back the message “SUCCESS.” We then lis-

ten for other commands such as FORWARD, REVERSE, RIGHT, LEFT,

STOP, and RANGE. The PDA sends the corresponding commands to

PDA Robot via the infrared socket.

// OnWireless connects to the command center over the wireless network. NOTE: YOU

// MUST connect to the command center before initializing the IrDA. If you initialize the

// IrDA first this button will be disable until the application is restarted. This will be fixed

// in the next version which can be downloaded at www.pda-robotics.com

void CPDABotDlg::OnWireless()

{

// Listen on the wireless socket for commands from the

// command center and forward them to PDA Robot on the

// Infrared socket.

UpdateData(TRUE);

m_hostname.GetWindowText(m_strServer);

m_username.GetWindowText(m_strUsername);

m_password.GetWindowText(m_strPassword);

CheckForAuthentication();

::SetTimer(this->CWnd::m_hWnd, 1, 1000, NULL);

}

bool CPDABotDlg::CheckForAuthentication()

{

if(!StartApplication())

{

return FALSE;

}

m_bClientConnected=true;

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char szHostName[25];

// Get the name of the PDA this is running and send it

// to the command Centre.

gethostname(szHostName,25);

m_pSocket->Send (szHostName,25,0);

char szUsername[255];

char szPassword[255];

strcopy(szUsername,m_strUsername);

strcopy(szPassword,m_strPassword);

//send the user name and the password

m_pSocket->Send (szUsername,255,0);

m_pSocket->Send (szPassword,255,0);

return TRUE;

}

// ConnectSocket Creates the CPDASocket which is derived from a CCeSocket

// and attempte to connect to the remote host that the control center is

// running on.

BOOL CPDABotDlg::ConnectSocket(LPCTSTR lpszHandle, LPCTSTR lpszAddress, UINT

nPort)

{

m_pSocket = new CPDASocket(CCeSocket::FOR_DATA);

if (!m_pSocket->Create())

{

delete m_pSocket;

m_pSocket = NULL;

this->m_status_window.SetWindowText( (LPCTSTR) CString("Can't create sock") );

return FALSE;

}

if(!m_pSocket->Connect(lpszAddress, nPort + 700))

{

this->m_status_window.SetWindowText( (LPCTSTR) CString("Failed to connect") );

delete m_pSocket;

m_pSocket = NULL;

return FALSE;

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}

return TRUE;

}

// Star tApplication sets the connection parameters and

// calls ConnectSocket. If the connection fails ensure

// that the Control Center (which acts as the Server )

// is running.

BOOL CPDABotDlg::Star tApplication()

{

m_strHandle="7";

m_hostname.GetWindowText(m_strServer);

m_nChannel=7;

if (ConnectSocket(m_strHandle, m_strServer, m_nChannel))

return TRUE;

else

{

this->m_status_window.SetWindowText( (LPCTSTR) CString("Connection Failed ") );

return FALSE;

}

// ReadPDAData() Is called when the CESocket signals that

// data has arrived from the Command Center. The data is

// a string indicating that the connection was successful

// or a Motion command that will be relayed to PDA Robots

// body.

void CPDABotDlg::ReadPDAData()

{

CString status_message;

char szMessage[512];

static int initialized;

u_long numbytes;

int ret;

// Ensure that we won't be blocked waiting here on the call

// to read the data.

ret = ioctlsocket ((SOCKET) m_pSocket, FIONREAD, &numbytes);

if( (ret == 0) && (numbytes > 0) )

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{

// Receive the data from Command Center

ret = recv ( (SOCKET) m_pSocket, &szMessage[0], numbytes, 0);

}

else{

return;

}

// Set the status to the last command so it can be displayed

// in the status edit box named m_status_window and used in the

// OnTimer() function to relay the commands to PDA Robot

LastStatus = szMessage;

// Note: The Timer was started when the Wireless link was

// Enabled and the data received is interpreted when the timer

// goes off.

}

void CPDABotDlg::OnTimer(UINT nIDEvent)

{

m_status_window.SetWindowText( (LPCTSTR) LastStatus);

if(LastStatus == "SUCCESS" )

{

// We have connected to the Command Center

m_status_window.SetWindowText( (LPCTSTR) CString("Connect Infrared") );

}else if(LastStatus == "FORWARD"){

// Instruct PDA Robot to move Forward via the IR Socket if

// an IrDA link has been established

if( m_bIrDAConnected )

{

send( Infrared_Socket, (const char *) "be", 2, MSG_DONTROUTE);

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}

}else if(LastStatus == "REVERSE" ){

// Instruct PDA Robot to move Reverse via the IR Socket if

// an IrDA link has been established

if( m_bIrDAConnected )

{

send( Infrared_Socket, (const char *) "ad", 2, MSG_DONTROUTE);

}

}else if(LastStatus == "LEFT" ){

// Instruct PDA Robot to move Left via the IR Socket if

// an IrDA link has been established

if( m_bIrDAConnected )

{

send( Infrared_Socket, (const char *) "ae", 2, MSG_DONTROUTE);

}

}else if(LastStatus == "RIGHT" ){

// Instruct PDA Robot to move Left via the IR Socket if

// an IrDA link has been established

if( m_bIrDAConnected )

{

send( Infrared_Socket, (const char *) "bd", 2, MSG_DONTROUTE);

}

}else if(LastStatus == "STOP" ){

// Instruct PDA Robot to Stop via the IR Socket if

// an IrDA link has been established

if( m_bIrDAConnected )

{

send( Infrared_Socket, (const char *) "cf", 2, MSG_DONTROUTE);

}

}else{

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// couldn't log on or we received some bad data

}

CDialog::OnTimer(nIDEvent);

}

Once the wireless connection to the command center (PC) and the

infrared connection has been established, we can now control the PDA

Robot remotely, seeing through the wireless camera (see Figure 9.7).

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Figure 9.7

PDA with wireless

card.

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195

The command center runs on a Windows 95 or better operating system

PC that is connected to the wireless network through a Network

Everywhere Cable/DSL Router. It has a Video Capture Card connected

to an X10 wireless video receiver.

From the command center, users can control PDA Robot remotely. It

can detect motion, as well as save and send images via file transfer

protocol (FTP) or simple mail transfer protocol (SMTP). When the

application starts, it listens for a connection from the PDA that is con-

trolling PDA Robot. When PDA Robot successfully logs in, users can

begin controlling the craft remotely, looking through its eyes. Figure

10.1 shows the main screen of the command center.

The Video Link

The following program is using the Video for Windows application

programming interface (API) provided by Microsoft. A window is cre-

ated in the dialog, with the Dialog window being the parent, and it is

registered as the video window.

void CBeamDlg::OnInitializeDriver()

{

// Display the video source window that allows the user to select the input

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Command Center

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BOOL code = capDlgVideoSource(h_capwin);

// Create the Capture window

h_capwin = ::capCreateCaptureWindow("PDABot Video",

WS_CHILD|WS_CLIPSIBLINGS|WS_VISIBLE|WS_EX_DLGMODALFRAME ,

20,

,320,

240,this->m_hWnd,0

);

// Hook into the video driver. Check up to 10 and use the first one encountered

for( int j=0; j<10;j++){

code = capDriverConnect(h_capwin, j);

if(code){

// Select the video source

code = capDlgVideoSource(h_capwin);

// Set the preview rate

code = capPreviewRate(h_capwin, 100);

// turn video previewing on

code = capPreview(h_capwin, TRUE );

break;

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Figure 10.1

Command center.

PDA 10 5/27/03 8:51 AM Page 196

}else{

// No Driver Detected

}

m_stretch_video.SetCheck(1);

// Add the name of the video driver to the title bar of the window

code = capDriverGetName( h_capwin, &szName[0], wSize );

if( code == TRUE )

{

title_text += " - Capture driver : ";

title_text += szName;

this->SetWindowText(title_text);

}

The video should now be displayed on the main window, as shown in

Figure 10.1. If the user has selected motion detection, stream the video

into a callback function, checking to see if anything has changed

between the first image that was stored in memory and the current

frame.

Motion Detection

void CBeamDlg::OnCheckVision()

{

if( m_check_vision.GetCheck() == 1)

{

m_radar_stat.SetWindowText("Motion Sense : ON");

// Disable stretch feature... the stretch requires significant processor cycles

if( m_stretch_video.GetCheck() == 1 )

{

m_stretch_video.SetCheck(0);

capPreviewScale(h_capwin, FALSE);

m_stretch_video.EnableWindow(FALSE);

this->InvalidateRect(NULL, TRUE);

}

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