Code

' -----[ Title ]-------------------------------------------------------
'
' File...... linetrack.BAS
' Purpose... Robot to follow Black Line BasicBoard -> IRD Line Detector
' Author.... Chuck Hellebuyck
' Started... August 10, 2002
' Updated... 


' -----[ Program Description ]-----------------------------------------
'
' This Program uses the BasicBoard to control a Servo robot platform. The
' robot has a Lynxmotion infrared 3 element line detector module mounted 
' under its platform. This program will drive the robot forward while it 
' scans for the black line under the detector. If the black line hits 
' one of the outer elements, the robot will correct back to center as 
' it moves forward. The object is to have the robot follow the line 
' from one end  to the other.
'
' P0       Left Detector Element Output
' P1       Center Detector Element Output
' P2       Right Detector Element Output
' P8       Left Wheel Servo
' P9       Right Wheel Servo

' -----[ Revision History ]--------------------------------------------
'
' 

' -----[ Variables & Constants ]---------------------------------------
'
LSENS var in0       'Left detector element
CSENS var in1       'Center detector element
RSENS var in2       'Right detector element

serv1 con p8		' Left wheel servo connection to P8
serv2 con p9		' Right wheel servo connection to P9


' -----[ Variables ]---------------------------------------------------
'
move var byte            	'robot movement variable 
x var byte               	'general purpose variable

' -----[ Initialization ]----------------------------------------------
'

' -----[ Main Code ]---------------------------------------------------
'

main:
if csens = 1 and lsens = 1 and rsens = 1 then lost	'Can't find line
if lsens = 0 and rsens = 0 then rest	'Both outer sensors see black
if lsens = 0 then left				'Black line sensed left
if rsens = 0 then right				'Black line sensed right
if csens = 0 then center			'Black line in center of robot

goto main						'Loop back and check sensors

'*** Line at center drive robot routine ***
center:
move = 5						'Set max movement to 5 units
for x = 1 to move					'Loop for 1 to 5 units
servo serv1, 1200, 1				'Drive left wheel forward
servo serv2, -1200, 1				'Drive right wheel forward
if lsens = 0 or rsens = 0 then main		'If black line left or right return
next							'Continue loop
goto main						'Return to main loop

'*** Line sensed at left, drive robot routine ***
left:
move = 5						'Set max movement to 5 units
for x = 1 to move					'Loop for 1 to 5 units
servo serv2, -1200, 1				'Drive right wheel forward
if lsens = 1 then main				'If black line not sensed then main
next							'Continue loop
goto main						'Return to main loop

'*** Line sensed at right, drive robot routine ***
right:
move = 5						'Set max movement to 5 units
for x = 1 to move					'Loop for 1 to 5 units
servo serv1, 1200, 1				'Drive left wheel forward
if rsens = 1 then main				'If black line not sensed then main
next							'Continue loop 
goto main						'Return to main loop

'*** Cannot find black line routine ***
lost:
servo serv1, 1200, 1				'Drive left wheel forward one unit
servo serv2, -1200, 1				'Drive right wheel forward one unit
if lsens = 0 or rsens = 0 or csens = 0 then main	'Check for line
goto lost						'Keep searching line not found

'*** Stop robot routine ***
rest:
pause 10						'Delay for 10 milliseconds
goto main						'Jump to Main loop

end