Re: Non-Comfort Alarms

[Kevin Hawkins <tivo@xxxxxxx>]

Title: [ukha_d] Re: Non-Comfort Alarms

        I'll have a shot as i'm just waiting for a download t complete - Newcastle accents take a bit of getting used t -

        James had an old alarm system and he deduced which were the wires that actually went t the sensors (eg the passive infra red detectors). He then used a chip called a CD4050 which converted the voltage that the panel expected t see int a standard level that most electronics use , probably +5V and Ground.  This is a bit like using a relay or an opto isolator that I talked t you about in my previous message. The 8255 PIO (Parallel input Output) is simply a chip that has a load of inputs (probably 8) each of which can be interrogated by your computer. So he has effectively just linked the PIR outputs int the PC as well as the panel simultaneously.

        I haven't actually found out if you have a home automation controller - are you running some PC software for this ? Obviously you have t get the information from the Alarm panel int your controller - if you are intending to use a PC as your controller then this restricts in a way how the information can be transferred. I think your original hope - and actually the neatest solution is a serial (RS232) interface. Otherwise each input has t have it's own wire t the PC - effectively a parallel data transfer. The PC does not have a nice way of taking parallel information in (it's not impossible it's just not nice). It gives parallel out through the printer interface port. Some electronics are needed t interface back in a parallel way and that is what James did - the 8255 gives the PC a parallel interface input. ( I know modern parallel ports are bi-directional before someone jumps on me).

        Let's wait & see how you get on with your plea t Scantronic for info -  & then tackle the options. If we have t deal with a parallel data interface then an external controller like HomeVision would do this with ease, or we need t be cute with the electronics interface to a PC. some people also make parallel t serial convertors that work with some HA applications. Have you a budget in mind - a more capable panel is another option that would certainly solve this problem at lower cost than say a HomeVision unit - but the HV would give far greater control options for later if you intend t get into Home Automation seriously.

        What's your current setup ?

        Kevin

> Does anyone know of a babelfish that
> will interpret this? :)
>
> Today I bought "Electronic Project Building For
> Beginners"
> and "Practical Remote Control Projects" maybe that gives you
> an idea
> of my practical electronic experience (I think I used t  know
> plenty
> of theory)
>
> One day I'll understand what half of you lot are talking about.
> Can
> we not go back t  queries in MS-Access where I'm on reasonably
> firm
> ground!!
>
> If you can break this down t  words of one syllable it'd be much
> appreciated.
>
> Mark (feeling very stupid)
>
> --- In ukha_d@y..., James Derrick <james@a...> wrote:
> > On Mon, 09 Jul 2001 10:40:40 -0000, you wrote:
> >
> > >Has anyone got any experience of interfacing with Alarm
> Systems
> other
> > >than comfort ones?
> >
> > I have the remains of a system used for years in a previous
> house. I
> > simply traced the zone input circuits (typically large
> resistors,
> and
> > a supression cap), worked out which was a supply rail and which
> was
> > the signal t  the controller and added a wire t  a CD4050
> level
> > shifter/ buffer. This was then linked up t  a 8255 PIO board in
> a
> PC.
> >
> > This worked a treat- the panel worked normally, and the PC
> had
> > independant monitoring of all inputs and outputs.
> >
> > TTFN,
> >
> > James
> > James Derrick    james@a..., Cramlington, Near
> Newcastle, England
> >                  Beyond the Horizon
> of the place we lived when we
> were young,
> >                  In a World of
> Magnets and Miracles. Pink Floyd.
>
>
>
>
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> http://www.automatedhome.co.uk
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