how add hysteresis in my code

tanveerriaz · Joined: 04 May 2012 Posts: 7

for Mike Walne.
this is prototype. i draw a sketch of my board.
i made this pcb for test code.
i understand the risks working on live mains.
i am not a programmer.
only a electronic/radio hobbyist.
my code work show voltage on lcd and on/off led.
i can not made relay driver board. and mains in put circuit.
i say when i complete it i show it.

Mike Walne · Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK

dorinm · Joined: 07 Jan 2006 Posts: 38

so, if you want some help (and thank's Mike, I do know what it means to live betveen 6kV lines Smile

), first do what Mike suggested and isolate the PIC from your mains, anything else could lead to undefined behaviour (or fun elecronic fail;) );
there's something you might want to consider: an isolation transformer is never a wrong bet ;) ...you could actually use a two-winded transfomer (one for pic, one for feeding the adc, common ground wont'n be a problem), and rectify one winding for feeding the adc of your pic; use a zero-crossing detector, and you'll know exactly when to sample, and you have plenty of time (50-60HZ = 20-16mseconds), to determine the actual voltage on your mains