' some crude autonomous vehicle software
'
'hardware is picaxe 18A
'L293D motor driver connected to outputs 0,1, and 2,3
'2 mini robot motors connect to the L293D and are attached to wheels via
'a gearbox to provide necessary higher torque (at the expense of speed)
'
'An LED is between pins 4 and 5 for simple signalling
'
'this program lets the robot wander toward light sensed by 2 LDRs
' slight improvements over initial photovore efforts, it works by:
'
' - measuring left and right ambient light values
' - if difference is above a threshold, turn toward the light a bit
' - else go straight a bit
' - instead of in-place turn (one wheel fwd, other backwd), use single motor to maintain forward motion
' - loop to measuring light values...  (loops several times per sec)



'define pinouts
symbol motor1A=0	'left motor
symbol motor1B=1

symbol motor2A=3	'right motor
symbol motor2B=2

symbol LDR1=1
symbol LDR2=2

symbol LED1A=4	'LED across these pins for now
symbol LED1B=5


'define variables
symbol commandb=b0
symbol tmp1b=b1

symbol execloop=b2	'execution loop counter
symbol tmpb1=b3

symbol randomw=w2
symbol randomb=b4

symbol tmpb2=b6
symbol tmpb3=b7

symbol diff=b8

'define constants
symbol leddly=250

symbol motorFwdOnDly=200	'delay while motors are on
symbol motorTurnOnDly=200	'delay while motors are on
symbol motorPWMloop=1	'numer of loops for crude motor PWM

symbol mindiff=3		'minimum difference in light values required to change direction

symbol actionDly=200	'delay between actions

init:
	gosub m1m2off
	gosub flashled	'let user know we're alive
	pause 6000
	randomw=4098


	pause actionDly		'wait a bit
	gosub flashled	'indicate command

start:
	
	readadc LDR1, tmpb2	'get light vals
	readadc LDR2, tmpb3
	
	
	if tmpb2>tmpb3 then 	'figure out which one is greater
		diff=tmpb2-tmpb3
		tmpb1=0
	else
		diff=tmpb3-tmpb2
		tmpb1=1
	endif
		
'	pause actionDly		'wait a bit
'	gosub flashled	'indicate command


	if diff>mindiff then		'if diff is above a threshold, then turn
'		on tmpb1 gosub m1m2rt, m1m2lt
		on tmpb1 gosub m2fwd, m1fwd
		pause motorTurnOnDly		'wait a bit
		gosub m1m2off
	else						'else go straight
		gosub m1m2fwd
		pause motorFwdOnDly		'wait a bit
		gosub m1m2off
	endif

	goto start
		
			
			
m1fwd:
	high motor1A
	low motor1B
	return

	
m1rev:
	low motor1A
	high motor1B
	return

	
m2fwd:
	high motor2A
	low motor2B
	return

	
m2rev:
	low motor2A
	high motor2B
	return

	
m1m2fwd:
	high motor1A
	low motor1B
	high motor2A
	low motor2B
	return

	
m1m2rev:
	low motor1A
	high motor1B
	low motor2A
	high motor2B
	return

	
m1m2lt:
	high motor1A
	low motor1B
	low motor2A
	high motor2B
	return
	
	
m1m2rt:
	low motor1A
	high motor1B
	high motor2A
	low motor2B
	return


	
m1m2off:
	low motor1A
	low motor1B
	low motor2A
	low motor2B
	return
	
	
led1on:
	high LED1A
	low LED1B
	return


led1off:
	low LED1A
	low LED1B
	return


flashled:	
	for tmp1b=0 to commandb
		gosub led1on
		pause leddly
		gosub led1off
		pause leddly
	next tmp1b
	return