' Demo program for March 2003 SiChip  PICAXE-08 article  Ver 1.2  9 March 2003
' Best assembled & tested with solderless "PICNIK" box as detailed SiChip Feb.03
' Refer http://picaxe.orcon.net.nz for background info & potential of PICAXE-08 
' MORE RELIABLE OPERATION REPORTED FROM 5V OR LESS (4.5V ?) 6V MAY BE TOO HIGH ?
' REF http://picaxe.orcon.net.nz/optocalc.jpg for a modified calculator counter !
' ******************************************************************************
' Extra parts = LDR, White LED, Red LED, 2 x 100 Ohm, 1 x 330 Ohm, piezo speaker
' LDR & illuminating light can be moved apart- maybe use lenses & light guides ?
' New commands here = sound, readadc, debug, pulsout, for-next & simple maths.
' Ref.PICAXE prog.editor .pdf help files,& BASIC Stamp manuals etc for insights
'       via Stan. SWAN ( MU@W, New Zealand )  => s.t.swan@massey.ac.nz <=       
'-------------------------------------------------------------------------------
' Byte variables          b0= LDR "resistance value"    b1= event counter 
'			  b2= pulse delay  in msec      b3= sound loop 
' Strictly only the LHS code below is needed. Remarks (') can be ignored 
'-------------------------------------------------------------------------------
sound 4,(100,10,80,10)  	'initial dual sounds to inform that powered up
   
ldrdemo:			' LDR resistance monitoring routine
 readadc 1,b0			' read LDR low resolution value via voltage divider  
  debug b0 			' show variable LDR value(s) to attached PC screen
   if b0 <160 then beeper	' warbling alert tones when LDR shaded 
    b2 = 250/b1			' produce delay value.NB max variable value is 255
    if b2 =0 then ldrdemo	' prevents LED flash when not yet triggered
  pulsout 2,1000		' pulse LED pin 2 for 1000x10 microsec =10millisec
 pause b2:pause b2:pause b2 	' more events give decreasing delay between pulses
goto ldrdemo			' continually loop unless LDR shaded
 
beeper: 			' piezo speaker 2 tone sound routine
 for b3= 1 to 3			' loop to sound tones 3 times
  sound 4,(100,20,80,20)	' repeating dual tones each 20 msec
  next b3			' sound loop increment
 b1=b1+1			' event counter increment
goto ldrdemo			' return to monitoring routine