Implementing a "normally open" relay

[Achilleas Mantzios]

Στις Τρίτη 06 Νοέμβριος 2007 13:42, γράψατε:
> Achilleas Mantzios wrote:
> > Hi,
> > i am building a home security system based on zoneminder under FreeBSD
> > 6.2. I think i have it all sorted out, except a way to drive an external
> > alarm upon camera motion.
> >
> >
> >
> > Have two states:
> >
> > a) (normal) Have the two wires isolated from eachother, ground, voltage
> > b) (alarm) Connect the wires together (shortcircuiting the EOL).
> >
> > Could it be done someway with /dev/cuad* /dev/lpt*
>
> Probably overkill, but you can buy general purpose relay boards driven
> from the parallel port, e.g.,
>
> http://www.electronic-kits-and-projects.com/3074.htm

Thank you Chris,
thats probably a good solution for commercial/industrial applications.

Bill (WKK) gave me an excellent idea about using a modem, and it works
very good.

>
> Chris

-- 
Achilleas Mantzios