Visual Basic Code (April 30, 2001 5:00 pm)

Option Explicit ' Variables must be defined

Dim flag As Boolean ' Allow for continuation of event

Dim X, Y As Integer ' Coordinate direction increment (-1,0,1)

Dim sDirection As String ' Character variable for robot heading

Dim bSetPoint As Boolean ' Initial starting point

Dim bBackwards As Boolean ' Backwards movement flag

'Private Sub cmdDraw_Click() ' Drawing routine

Public Sub PlotRobot() ' Robot plotting routine

' Dim time As Long ' Pause counter

' flag = True ' Allow for event continuation

' Do While flag ' Draw a line until stopped

DoEvents ' Allow for other actions to occur

Call Direction ' Get plotting direction

If picDraw.CurrentX > 0 And picDraw.CurrentX < 10000 And _

picDraw.CurrentY > 0 And picDraw.CurrentY < 6000 Then

If frmSerial.sInstr = "B" Then ' Direction dependent line color

picDraw.PSet Step(X, Y), vbRed ' Draws a red line

Else

picDraw.PSet Step(X, Y), vbBlue ' Draws a blue line

End If

Else

' Error message

MsgBox "Robot out of bounds!" & vbNewLine & _

"Robot position will be reset"

' Reset position

picDraw.CurrentX = 5000 ' Initialize x-coordinate

picDraw.CurrentY = 3000 ' Initialize y-coordinate

sDirection = "N" ' Initialize direction

' Break from movement

' flag = False

End If

' For time = 1 To 1000000: Next ' Pause

' Display realtime plotting information to user

lblInfo.Caption = "Plotting current position"

lblPosition.Caption = "X: " & picDraw.CurrentX & " Y: " & picDraw.CurrentY

' Loop

lblInfo.Caption = "Program Stopped Successfully!"

End Sub

Private Sub cmdExit_Click()

End ' Exit program

End Sub

Private Sub cmdStop_Click() ' Stop action

flag = False ' Set flag to stop action

End Sub

Private Sub Form_Load()

picDraw.CurrentX = 5000 ' Initialize x-coordinate

picDraw.CurrentY = 3000 ' Initialize y-coordinate

sDirection = "N" ' Initialize direction

End Sub

Private Sub Direction() ' Plotting of BOEBot path

If frmSerial.bDirChange Then ' Allow direction change?

Select Case frmSerial.sInstr ' Determine direction

Case "F" ' Forward - no need to alter direction

If bBackwards Then ' Moving backwards?

Select Case sDirection ' Alter the direction

Case "N": sDirection = "S"

Case "S": sDirection = "N"

Case "E": sDirection = "W"

Case "W": sDirection = "E"

End Select

bBackwards = False ' Moving forwards

End If

Case "B" ' Backward

bBackwards = True ' Set flag to let user know going backwards

Select Case sDirection ' Alter the direction

Case "N": sDirection = "S"

Case "S": sDirection = "N"

Case "E": sDirection = "W"

Case "W": sDirection = "E"

End Select

Case "R" ' Right

If bBackwards Then ' Moving backwards?

Select Case sDirection ' Backwards logic

Case "N": sDirection = "W"

Case "S": sDirection = "E"

Case "E": sDirection = "N"

Case "W": sDirection = "S"

End Select

bBackwards = False ' Moving right

Else

Select Case sDirection ' Fowards logic

Case "N": sDirection = "E"

Case "S": sDirection = "W"

Case "E": sDirection = "S"

Case "W": sDirection = "N"

End Select

End If

Case "L" ' Left

If bBackwards Then ' Moving backwards?

Select Case sDirection ' Forwards logic

Case "N": sDirection = "E"

Case "S": sDirection = "W"

Case "E": sDirection = "S"

Case "W": sDirection = "N"

End Select

bBackwards = False ' Moving left

Else

Select Case sDirection ' Forwards logic

Case "N": sDirection = "W"

Case "S": sDirection = "E"

Case "E": sDirection = "N"

Case "W": sDirection = "S"

End Select

End If

End Select

frmSerial.bDirChange = False ' Do not allow direction change

End If ' End direction change

Select Case sDirection ' Set plot direction

Case "N" ' North

X = 0: Y = -1

Case "S" ' South

X = 0: Y = 1

Case "E" ' East

X = 1: Y = 0

Case "W" ' West

X = -1: Y = 0

End Select

End Sub