'bikeamph.bas for Picaxe-08M driven 'CATEYE Velo1' bike computer conversion.
'Suits educational output current monitoring of small 1W PV or wind gene 
'via simple 1W 1 Ohm supply shunt resistor, with voltage readadc10 measured.
'Schematic (draft)=> www.picaxe.orcon.net.nz/bikeamph.gif -suits breadboard!
'Initial solderless small PV layout =>www.picaxe.orcon.net.nz/bikeamph.jpg
'Thanks to Glen's A1 wind gene site => www.thebackshed.com for initial ideas
'For 'Silicon Chip' article Feb. 2007. Via=> stan.swan@gmail.com 23/12/2006

shunt:  
readadc10 1, w1      ' approx w1 range 1 at 5mA to 30 at 100mA thru' 1 Ohm
'sertxd (#w1,13,10)  ' useful w1 'F8' check point-comment in/out as need be
if w1 <=1 then shunt ' gives bike comp. zero reading on very low I (~<5mA)

w2=600/w1            ' adjust top '600'for Picaxe supply calib. (600=~4.5V) 

 high 4		     ' Output pulse code for bike computer,fed to pin 4
 pause w2            ' via 100nF capacitor & parallel LED. Some scope for 
 low 4               ' tweaking,but bike comp.times out if pause >~1000ms 
 pause w2            ' and upper detection range ~30mS (~100km/hr)

goto shunt