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Bots / The Ultimate Palm Robot/ Mukhar & Johnson / 222880-6 / Chapter 7

186 The Ultimate Palm Robot

Sub ReadRange()
Dim r as String
Dim numbytes as Integer
Dim readSensorStr as String
Dim err as Integer

range = -1
readSensorStr = "BD1AD1"+chr(13)
err = serialsend(readSensorStr, len(readSensorStr))
numbytes = sysinfo(5)
LabelNumBytesValue.label = str(numbytes)
If (numbytes > 0) Then
SerialReceive(r,numbytes,3.0)
range = val(r)
LabelRangeValue.label = str(range)
EndIf
Return
End Sub

The flow of this program is the same as it was before. When the Start button
is tapped, the application runs a loop that reads the sensor, and does a little jig
if it detects an object with sensor 1. When the Stop button is tapped, the pro-
gram ends. Notice that while the functions to open, read, and write the serial
port are different in NS Basic than in HotPaw Basic, the concept is still the
same. The program opens the port, and reads and writes data to the SV203 as
simple text strings. You can find more information on the serial port functions
and other functions in the documentation for NS Basic.

Although we will not go through this code line by line, we will point out
some of the functions we used. Within the LoopMethod( ) function, the call
to the SysEventAvailable( ) function tells us whether the user has tapped a
button or control. If this happens, the program assumes that the user wants
to stop. Within the ServoControl( ) function, the serialsend(String, Integer)
function sends a string to the serial port. This is the function that sends our
commands to the SV203. Within the ReadRange( ) function, the sysinfo(5)
function calls and returns the number of bytes waiting to be read from the se-
rial port. The SerialReceive( ) function reads those bytes from the serial port.

P:\010Comp\Bots\880-6\ch07.vp
Monday, May 12, 2003 4:29:27 PM