Drip Governor - A most valuble first hack

[mike_biddell]

peachy2.jpg
Have completed the PICAXE version of the light switch. All of it is completely alterable by changing the software. Runs great in the simulator................ it's a dynamic simulator and altering the LDR above and below a threshold switches the relay on and off alternately. Pushing the mode select push button turns the relay OFF and generates a nice little square wave which would drive the mirrors for scanning. Pushing the button again, puts it back into drip-valve mode. The PAUSE statements in the software will need altering to suit the real setup. The chip is programmed using a serial link. The transistor and relay can be replaced with a FET switch circuit of your choice. The software follows:-

low 0 'initialise outputs to OFF
low 4
main:
readadc 1, b1 'read value on pin 1 into variable b1
if b1 > 100 then 'if laser pointing at LDR
pause 1000
goto onoff 'turn the drip valve ON
endif
if pin3 = 1 then ' if button pressed scan-mode required
goto scanmode
endif
goto main

onoff:
high 2 'turn transistor ON
readadc 1, b1 'check if laser is demanding OFF
if b1 > 100 then 'only exit this loop if laser fires again
pause 1000
low 2 'turn transistor OFF
goto main
endif
goto onoff ' back around if no OFF signal from laser

scanmode:
pause 2000 'wait to prevent bounce
low 2 ' make sure drip valve is OFF
high 4 ' set mirror squarewave drive on pin 0
pause 100 ' alter this to suit the mirror slew rate
low 4 ' mirror square wave 0
if pin3 = 1 then
pause 1000
goto main 'exit scanmode if mode pushbutton pressed
endif
goto scanmode