>
> >>Hi all
> >>
> >>I want to make a home security system using a keypad and lcd (outdoors)
> >>IRsensor and everyboddy has his own code ,rs232 to display something on pc
> >>,when someone has put the system on or off
> >>date and hour et...
> >>Dus someone know where i can get info ??? I am learning to program the
> >PIC's
> >>and have all the hardware to progam them.
> >>I have look almost everywhere and could'n find something HAI.

While no one may not have put each of the pieces together, they all exist
separately. Simply look in the archives (Can someone post the URL where
the archives can be found?) for the individual parts, RS-232, keypad, and
LCD.

The toughest part is going to be the sensors. Door loops are subject to quite
a bit of noise. In my prototype alarm system (which used a button and beeper
interface, i.e. three beeps to activate, two to disarm, 4 for status) the
door loop falsely triggered until I debounced with a 200ms debounce routine.

The slickest part of that prototype was the use of cheap PIR floodlights
as motion detectors. Instead of spending $35-$50 apiece for 12V PIRs, I bought
a $10 motion flood and hacked it. While I know it's possible to strip the
flood down to the circuit board and a low voltage DC interface, it was more
expidient to utilize the existing 120V AC interface that the floodlight uses.
Here's what I did.

1) Removed the flood sockets and cut the 120V interface wires.
2) Attached the 120V interface wires to an optoisolator and a reversed biased
led through a 10Kohm 2W resistor.
3) Drove a 12V signal through the transistor side of the optoioslator, creating
a low voltage interface through the house and to the PIC.
4) Attached the 12V interface to a second optoioslator which then drove the
PIC input pin.

The result is an extremely clean optoisolated 60 Hz square wave whenever the
motion flood was triggered. Even better they fit in standard round electrical
boxes that are easily mounted in the ceiling.

Finishing this project is on my infamous 9 billion things to do list, but
the prototype worked quite well.

Hope this helps,

BAJ