'PICAXE-08 serial INPUT data control link for July 2003 SiChip article  V 1.0 15/5/03
'Needs matching output program & hardware at sender PICAXE for receiver piezo control 
'Connect piezo to PICAXE-08 pin 0 - ref article for use as programming feedback too. 
'2 wires between units only - data on pin 4 linking both & simple ground return
'Inputs such high impedance that even damp string (~ 1MOhm) may be used as conductor!
'Variable b0= sender switch status (0=off/low,1=on/high) with 10k pulldown resistor
'NB -serial link decoding overheads may mean time delays (?)-easily *pause* tweaked.  
'Via Stan. SWAN (MU@W,New Zealand)  => s.t.swan@massey.ac.nz <=
'------------------------------------------------------------------------------------
' Lines beginning ' are program documentation & may be ignored if need be.
' Program available for web download =>www.picaxe.orcon.net.nz/rx.bas
'------------------------------------------------------------------------------------
 
state:				' procedure to serial data read sender switch state 
 serin 4,n2400,b0		' set up serial input on pin 4 & wait for b0 value
if b0 =1 then fastbeep		' check b0 & jump to fastbeep if =1(ON) else continue 

slowbeep:			' slow beep routine when switch is low (OFF)
 sound 0,(80,20)		' 20 ms lazy beep to piezo attached direct to pin 0 
 pause 1000			' 1 sec delay (may need altering to synch. ?)
goto state			' return to serial link switch reading input
  
fastbeep:			' fast beep routine when switch is high (ON)
 sound 0,(100,10)		' 10 ms higher pitched urgent beep to pin 0 piezo
 pause 250			' 1/4 sec delay ( may also need altering ?)
goto state			' return to serial link switch reading input